f4a42/f4a51 operation, diagnosis and repair · f4a42 and f4a51 automatic transaxle overview as with...

F4A42/F4A51 Operation, Diagnosis and Repair


TABLE OF CONTENTS INTRODUCTION AND OBJECTIVES ................................................................... 1 F4A42 AND F4A51 AUTOMATIC TRANSAXLE OVERVIEW.................................. 2 ACRONYMS ...................................................................................................... 4

GENERAL DESCRIPTION ................................................................................... 5 MODULE 1 F4A42/F4A51 TRANSAXLE IDENTIFICATION................................. 7

IDENTIFICATION................................................................................................ 7 MODEL DESIGNATION....................................................................................... 7 AUTOMATIC TRANSMISSION FLUID .................................................................. 9

ACTIVITY 1.1 TRANSAXLE IDENTIFICATION ................................................. 10 MODULE 2 MECHANICAL COMPONENTS ........................................................ 11

MECHANICAL COMPONENTS .......................................................................... 11 TRANSAXLE CASE ........................................................................................... 11 TORQUE CONVERTER ..................................................................................... 13 MANUAL CONTROL LEVER.............................................................................. 14 VALVE BODY LOCATION.................................................................................. 15 ACCUMULATORS............................................................................................. 18 ACCUMULATOR SPRINGS................................................................................ 18

ACTIVITY 2.1 VALVE BODY REMOVAL ........................................................... 19 TASK ONE: VALVE BODY REMOVAL................................................................ 19 TASK TWO: STRAINER AND 2ND BRAKE SEAL REMOVAL ................................ 20 TASK THREE: ACCUMULATOR REMOVAL ....................................................... 21 TASK FOUR: MANUAL LEVER REMOVAL ........................................................ 21 SPEEDOMETER GEAR (2001 MODEL YEAR WITH VSS) ................................... 22 OIL PUMP......................................................................................................... 23 OIL FILTER ...................................................................................................... 24

ACTIVITY 2.2 TRANSAXLE DISASSEMBLY...................................................... 25 TASK ONE: CASE SEPARATION ....................................................................... 25 TASK TWO: OIL FILTER, OIL PUMP AND INPUT SHAFT REMOVAL................... 25 TASK THREE: CLUTCH AND GEARTRAIN REMOVAL ....................................... 26 TASK FOUR: OUTPUT SHAFT REMOVAL.......................................................... 27 CLUTCHES ...................................................................................................... 30

Underdrive Clutch 30 Reverse Clutch and Overdrive Clutch 32 Balance Pistons 34

BRAKES (HOLDING CLUTCHES) ...................................................................... 35 Low/Reverse Brake 35 Second Brake 36 One-Way Clutch 37

PLANETARY GEAR SETS.................................................................................. 38 DIFFERENTIAL................................................................................................. 39

Transfer Drive Gear 40 Output Shaft/Transfer Driven Gear 41

MODULE 3 POWERFLOW ................................................................................ 42

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PARK AND NEUTRAL........................................................................................42 REVERSE .........................................................................................................43 FIRST GEAR .....................................................................................................44 SECOND GEAR ................................................................................................45 THIRD GEAR ....................................................................................................46 FOURTH GEAR.................................................................................................47

ACTIVITY 3.1 PLANETARY CARRIER...............................................................48 CLUTCH AND GEARTRAIN ...............................................................................49

ACTIVITY 3.2 GEAR RATIOS ...........................................................................50 ACTIVITY 3.3 TRANSAXLE ASSEMBLY ............................................................51

TASK ONE: TRANSFER GEAR INSTALLATION...................................................51 TASK TWO: L/R AND 2ND BRAKE SET-UP.........................................................51 TASK THREE: OUTPUT SHAFT INSTALLATION AND SETUP .............................53 TASK FOUR: PARKING PAWL INSTALLATION ..................................................54 TASK FIVE: PLANETARY CARRIER INSTALLATION ...........................................54 TASK SIX: UNDERDRIVE AND OVERDRIVE/REVERSE CLUTCH SETUP ..........55 TASK SEVEN: OIL PUMP INSTALLATION ..........................................................56 TASK EIGHT: CONVERTER HOUSING INSTALLATION ......................................56

MODULE 4 VALVE BODY/HYDRAULIC CONTROL SYSTEM...............................58 CHECK BALLS..................................................................................................60 PRESSURE CONTROL VALVES AND SOLENOID VALVES .................................62

Operation 62 REGULATOR VALVE.........................................................................................63 TORQUE CONVERTER PRESSURE CONTROL VALVE.......................................64 DAMPER CLUTCH CONTROL VALVE AND DAMPER CLUTCH SOLENOID VALVE.........................................................................................................................66

Operation 66 HYDRAULIC OPERATION..................................................................................68

Park and Neutral 68 Reverse 70 First Gear 72 Second Gear 74 Third Gear 76 Fourth Gear 78

MANUAL VALVE ...............................................................................................80 Operation (P/N) 80 Operation (R) 82 Operation (D) 84

SWITCH VALVE ................................................................................................86 FAIL-SAFE VALVE A .........................................................................................90 FAIL-SAFE VALVE B.........................................................................................90

ACTIVITY 4.1 VALVE BODY DISASSEMBLY......................................................91 ACTIVITY 4.2 HYDRAULIC OPERATION...........................................................92 MODULE 5 ELECTRONIC CONTROL SYSTEM...................................................97

ELECTRONIC COMPONENTS ...........................................................................97

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POWERTRAIN CONTROL MODULE (PCM) ........................................................ 98 PCM CONNECTOR ........................................................................................... 99 SYSTEM CONSTRUCTION DIAGRAM.............................................................. 100 SENSORS AND ACTUATORS .......................................................................... 101 INPUT SHAFT SPEED SENSOR/OUTPUT SHAFT SPEED SENSOR ................. 102

Circuit Operation 103 Vehicle Speed Signal 103

ACTIVITY 5.1 INPUT SHAFT AND OUTPUT SHAFT SPEED SENSORS ............. 104 CRANKSHAFT POSITION (CKP) SENSOR ........................................................ 106

Circuit Operation 106 ACTIVITY 5.2 CRANKSHAFT POSITION SENSOR........................................... 107

THROTTLE POSITION SENSOR ...................................................................... 108 Circuit Operation 108 Throttle Position Sensor Adjustment 108

ACTIVITY 5.3 THROTTLE POSITION SENSOR ............................................... 110 TPS WIRE COLOR 110 VOLTAGE READING 110

ATF TEMPERATURE SENSOR ........................................................................ 112 Circuit Operation 112

ATF TEMPERATURE CONTROL...................................................................... 113 ACTIVITY 5.4 AUTOMATIC TRANSAXLE FLUID TEMPERATURE SENSOR...... 114

Park/Neutral Position Switch 115 Circuit Operation 115

ACTIVITY 5.5 TRANSAXLE RANGE SWITCH/PARK/ NEUTRAL POSITION SWITCH (INHIBIT SWITCH) CONTINUITY CHECK .......................................... 116

TRANSAXLE CONTROL .................................................................................. 118 ACTIVITY 5.6 PARK/NEUTRAL POSITION SWITCH AND CONTROL CABLE ADJUSTMENT............................................................................................... 119

A/C DUAL PRESSURE SWITCH...................................................................... 120 Circuit Operation 120

STOPLIGHT SWITCH...................................................................................... 120 Circuit Operation 121

AUTO-CRUISE CONTROL............................................................................... 122 Circuit Operation 122

ACTIVITY 5.7 STOPLIGHT SWITCH CHECK .................................................. 123 SOLENOID VALVES ....................................................................................... 124

Circuit Operation 126 ACTIVITY 5.8 SOLENOID VALVE CHECK ...................................................... 127

TASK ONE – ACTUATOR TEST ....................................................................... 127 TASK TWO – VIEW DATA LIST........................................................................ 128 AUTOMATIC TRANSAXLE (A/T) CONTROL RELAY.......................................... 129

Circuit Operation 130 ACTIVITY 5.9 A/T CONTROL RELAY CHECK ................................................ 131

AUTOSTICK SELECT SWITCH........................................................................ 132 Circuit Operation 133

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ACTIVITY 5.10 AUTOSTICK SELECT SWITCH................................................134 SWITCH POSITION .........................................................................................134 UPSHIFT.........................................................................................................134 DOWNSHIFT...................................................................................................134 CONTROL OVERVIEW ....................................................................................135

Shift Control 135 Shift Pattern Control 135 Select Switch and Shift Switch 135

AUTOSTICK....................................................................................................136 ADAPTIVE MEMORY.......................................................................................138

Hydraulic Control During Gear Shifts 139 Clutch-to-Clutch Control 139 Feedback Control and Learning Control 140 Functional Learning 140 Driver Learning 140 Damper Clutch Control 142

LIMP-IN (FAIL-SAFE) FUNCTION AND DIAGNOSIS..........................................144 LIMP-IN (FAIL-SAFE) OPERATION (CONTROL RELAY OFF) .............................144 FAIL-SAFE VALVE A OPERATION ...................................................................146 FAIL-SAFE VALVE B OPERATION ...................................................................146 MAJOR LIMP-IN..............................................................................................146 MINOR LIMP-IN ..............................................................................................146

Diagnostic Codes 146 Display Sequence 147 Memorization 147 Diagnostic Code Deletion 147

DATA LIST......................................................................................................148 ACTUATOR TEST............................................................................................149 AUTOSTICK STOP COMMAND (MPI) ...............................................................149

MODULE 6 DIAGNOSIS ..................................................................................150 N-RANGE LAMP..............................................................................................150

ACTIVITY 6.1 N-RANGE LAMP FUNCTIONS....................................................151 ACTIVITY 6.2 TORQUE CONVERTER STALL TEST .........................................152

TORQUE CONVERTER STALL TEST RESULTS ...............................................153 ACTIVITY 6.3 CLUTCH TESTS .......................................................................154 ACTIVITY 6.4 HYDRAULIC PRESSURE TEST..................................................155 ACTIVITY 6.5 STANDARD HYDRAULIC PRESSURE TEST ...............................156 SPECIAL TOOLS ............................................................................................158 GLOSSARY ....................................................................................................166

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INTRODUCTION AND OBJECTIVES Introduced in the 2001 Stratus and Sebring Coupes, the F4A42 and F4A51 are a new generation of fully electronically shifted transaxles. By using a fully electronically controlled design, the driver experiences a consistent shift quality and feel.

The purpose of this course is to provide training on DaimlerChrysler Corporations “F4A42 and F4A51 Electronic Transmission Operation, Diagnosis and Repair”.

Upon completion of this course you will be able to:

• Identify the F4A42 and F4A51 automatic transaxle by decoding the ID tag. • Disassemble, evaluate, reassemble, setup and make all necessary

adjustments to the transaxle and all subassemblies. • Identify all mechanical components. • Demonstrate all gear ratios using a planetary gear stack. • Identify and describe all hydraulic components. • Diagnose hydraulic malfunctions. • Identify the hydraulic flow and solenoid actuation necessary to achieve all

gear ratios. • Perform electrical related DRBIII® activities to identify all direct inputs and

outputs. • Interpret appropriate shift schedules and determine if there is a malfunction

or if the vehicle is operating properly. • Diagnose and recommend the proper steps needed to perform a repair.

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F4A42 AND F4A51 AUTOMATIC TRANSAXLE OVERVIEW As with other electronically controlled transaxles the F4A42 and F4A51 transaxles utilize a torque converter and gear train (fig. 1). The torque converter is a 3-element, single-stage, 2-phase type with a built-in lock-up clutch. The gear train consists of three multi-disc clutches, two multi-disc brakes, a one-way clutch and two planetary gear sets. Each planetary gear set consists of a sun gear, carrier, pinion gears, and annulus gear. These newly developed transaxles combine the highest-precision electronic and mechanical technology to provide a new era in automatic transaxle performance.

Figure 1 F4A42/F4A51 Transaxle (2001 Model Year Shown)

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1 Rear of Transmission 6 One-Way Clutch 2 Overdrive Clutch 7 Output Gear 3 Reverse Clutch 8 Underdrive Clutch 4 Second Brake 9 Front of Transmission 5 Low/Reverse Brake

Figure 2 F4A42/F4A51 Geartrain

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ACRONYMS The following is a list of acronyms used throughout this publication:

• A/T Automatic Transaxle • ATF Automatic Transmission Fluid • DCC Damper Control Clutch • DRB Diagnostic Readout Box • DTC Diagnostic Trouble Code • ECU Electronic Control Unit (Manual Transmission) • EMCC Electronically Modulated Converter Clutch • FIPG Form-in-Place Gasket • FWD Front Wheel Drive • K-Ohms One Thousand Ohms • L/R Low-Reverse Brake • MDS Mopar Diagnostic System • OD Overdrive Clutch • ORC Over Running Clutch • OWC One-Way Clutch • PCM Powertrain Control Module (Automatic Transmission) • PNP Park/Neutral Position Switch • RC Reverse Clutch • TCC Torque Converter Clutch • TSB Technical Service Bulletin • UD Underdrive Clutch • 2nd Second Brake

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GENERAL DESCRIPTION The F4A42 and F4A51 automatic transaxles come in two models. Although they are similar in appearance there are several mechanical differences. Refer to Table 1 for model specifications.

Table 1 F4A42/F4A51 Transaxle Specifications

ITEMS SPECIFICATIONS

Transaxle model F4A42 F4A51

Engine model 4G64 (2.4L) 6G72 (3.0L)

Type 3-element, 1-stage, 2-phase

Torque converter clutch

Provided (3rd to 4th)

Torque converter

Stall torque ratio 1.85 2.04

Transaxle type 4-speed forward, 1-speed reverse full automatic

1st 2.842 2.842

2nd 1.529 1.495

3rd 1.000 1.000

4th 0.712 0.731

Gear ratio

Reverse 2.480 2.720

Final gear ratio (differential gear ratio) 4.042 3.735

Number of underdrive clutch discs 4

Number of overdrive clutch discs 4

Number of reverse clutch discs 2

Number of low/reverse brake discs 6

Number of second brake discs 3 4

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Notes:

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MODULE 1 F4A42/F4A51 TRANSAXLE IDENTIFICATION

IDENTIFICATION The F4A42 transaxle is found behind the 2.4L engine and the F4A51 transaxle is normally found behind the 3.0L engine. The bell housing bolt patterns are different and do not interchange between the 2.4L and 3.0L engines.

MODEL DESIGNATION A model number consisting of 11 digits is used to identify the transaxles. Each digit or pair of digits is used to provide specific information (fig. 3).

• F = Drive Axle • 4 = Forward Speeds • A = Transaxle Type • 42 = Capacity (duty rating) • K = Manufacturing Plant • 1 = Development (build) Sequence • M = Final Drive Ratio • 8 = Speedo Gear Ratio • A = One-Way Clutch & Planetary Ratio • 5 = Manufacturing Use Only

Proper identification of the F4A42 and F4A51 transaxles is important for the following reasons:

• Ordering parts • STAR assistance • Zone assistance • Researching TSB applicability

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Figure 3 Model Designation Identification

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AUTOMATIC TRANSMISSION FLUID The type of automatic transmission fluid used in the F4A42 and F4A51 automatic transaxles is Diamond ATF SP IIM, Diamond ATF SP III or a Mopar equivalent. The use of a newly developed ATF (ATF-SPII) ensures a longer ATF service life. Fluid information is found on a label at the top of the dipstick.

Caution: Using the incorrect transmission fluid may cause poor shift quality or torque converter shudder.

If the fluid level is low, the oil pump draws in air along with the fluid, which causes bubbles to form inside the hydraulic circuit. This causes a hydraulic pressure drop, late shifting, slipping of the clutches and brakes, and transmission overheating. If there is too much fluid, the internal rotating transaxle components can churn up the fluid, causing foam and a low fluid level indication. In either case, air bubbles can cause overheating and oxidation of the fluid which can interfere with normal valve, clutch, and brake operation. Foaming can also result in fluid escaping from the transaxle vent, and may appear as a leak.

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ACTIVITY 1.1 TRANSAXLE IDENTIFICATION

For this activity you will identify the transaxle on the bench using the Service Manual.

1. Using a F4A42 or F4A51 Transmission on a bench, locate and identify the following transmission components:

• Identification Label • Input and Output Speed Sensors • Vehicle Speed Sensor (VSS)-(2001 Model Year Only) • Transaxle Solenoid Connector

2. Record the transmission tag number

3. Record the first five characters of the tag number

These characters represent the type and capacity of the transaxle.

4. Record the next two characters of the tag number

These numbers represent the manufacturing plant and development sequence.

Example: K1 – the transaxle was built in Kyoto works, first design.

5. Record the last four characters of the tag number

6. Why is the information contained in the tag number important?

7. How do you remove the solenoid connector from the transmission?

8. The fluid identification information is stamped in the dipstick.

True False

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MODULE 2 MECHANICAL COMPONENTS

This module covers the following transaxle components:

MECHANICAL COMPONENTS • Torque converter • Oil pump • Clutches • Brakes (holding clutches) • Planetary gear set

Caution: The second brake retainer oil seal (fig. 4) must be removed before removing the transaxle powertrain components from the case or damage to the seal will occur.

1 Strainer 2 Second Brake Retainer Oil Seal Figure 4 Second Brake Retainer Oil Seal

TRANSAXLE CASE The F4A42 and F4A51 transaxles utilize a split case design consisting of the converter housing, transaxle case, rear cover, and valve body cover (fig. 5). The case halves must be separated to gain access to the filter. All gasket surfaces are sealed with form-in-place gasket (FIPG). Also, the names of hydraulic check ports are embossed on the casing to facilitate hydraulic checks (fig. 6).

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1 Transaxle Case 4 Oil Filter 2 Rear Cover 5 Converter Housing 3 Valve Body Cover 6 Bearing Retainer

Figure 5 Transaxle Casing

1 DCC Release Check Port 6 Transaxle Case 2 Reverse Clutch Check Port 7 Low/Reverse Brake Check Port 3 Rear Cover 8 Underdrive Clutch Check Port 4 Overdrive Clutch Check Port 9 2nd Brake Check Port 5 Torque Converter Housing 10 DCC Applied Check Port

Figure 6 Hydraulic Check Ports

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TORQUE CONVERTER The torque converter in the F4A42 and F4A51 is a damper-sprung lock-up mechanism (fig. 7).

• The torque converter consists of an impeller, a turbine and a stator. • The rotating impeller throws oil against the turbine causing it to rotate the

input shaft of the transaxle. • The turbine also throws oil against the stator causing it to rotate. • The stator consists of a vaned cover and an overrunning clutch. Because the

stator is allowed to turn in one direction only torque is multiplied. If the stator fails there is no torque multiplication, resulting only in a fluid coupling.

• The torque converter achieves lock-up by applying the damper clutch according to load, engine temperature and speed.

1 Damper Spring Figure 7 Torque Converter

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MANUAL CONTROL LEVER The manual control lever is fitted to the top of the valve body and is linked to the parking roller rod and manual control valve pin (fig. 8). A detent mechanism is provided to improve the gearshift feeling during manual selection. When the manual control lever is moved to the parking position, the parking roller rod moves along the parking roller support and pushes up the parking sprag. As a result, the parking sprag meshes with the transfer driven gear (parking gear), locking the output shaft. To minimize the operating force required, a roller is fitted to the end of the rod.

Caution: When removing the park mechanism, the 2nd O-ring comes off before removing the shaft to keep a piece from lodging in the pinhole.

1 Parking Roller Rod 5 Parking Gear 2 Inhibitor Switch 6 Parking Sprag 3 Parking Roller Support 7 Detent Spring 4 Spring 8 Manual Control Lever

Figure 8 Manual Control Lever

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VALVE BODY LOCATION The valve body is mounted vertically to the side of the automatic transaxle toward the front of the vehicle, reducing the automatic transaxles overall height (fig. 9). A solenoid valve and pressure control valve are used for each clutch and brake. The line pressure is regulated by a regulator valve. In the event of a solenoid valve fault, the switch valve and limp-in valve arrangement enables operation in 3rd gear or reverse.

Note: Before removing the valve body you must remove the solenoid harness connector snap ring.

1 Valve Body

Figure 9 Valve Body Location

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There are several bolts of different lengths used to mount the valve body to the transaxle (figs. 10 and 11).

Caution: When removing the valve body, there are four 70mm bolts that do not need to be removed. Removal of these four bolts causes the top of the valve body to come off and parts may be lost or damaged.

1 105 mm 5 38 mm 2 75 mm 6 20 mm 3 70 mm (Do Not Remove) 7 Fluid Temperature Sensor 4 45 mm

Figure 10 Valve Body Mounting Bolt Location

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1 105 mm 4 45 mm 2 75 mm 5 38 mm 3 70 mm 6 20 mm

Figure 11 Valve Body Mounting Bolts

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ACCUMULATORS An accumulator is a spring-loaded device designed to cushion clutch engagement according to engine torque. The accumulator absorbs a certain amount of fluid pressure from the circuit during clutch engagement. Without an accumulator, the rapid build up of line pressure causes a very quick clutch apply which creates a harsh shift. The clutches and brakes shown in Table 2 below have accumulators in their circuits.

Table 2 Accumulators

Functional Name Accumulator Number Low/Reverse Brake 1

Underdrive Clutch 2

Second Brake 3

Overdrive Clutch 4

ACCUMULATOR SPRINGS The accumulator springs are specific to the accumulator function. The springs are rated at different levels of stiffness, depending on application, and must be installed into the correct accumulator bore or transmission shift quality may be affected. Accumulator springs can be identified by a blue colored pattern on the end of the spring. Table 3 below aids in identifying the springs.

Table 3 Accumulator Springs

Number of Springs Name Identification “Bluing” 2 Low-Reverse Brake None

2 Underdrive Clutch Half of the surface

2 Second Brake Whole surface

1 Overdrive Clutch None

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ACTIVITY 2.1 VALVE BODY REMOVAL

For this activity you will remove the valve body, 2nd brake seal, accumulators and manual lever from the transaxle on the bench.

TASK ONE: VALVE BODY REMOVAL 1. Remove the bolts securing the valve body to the transaxle case, noting the number

and length of each bolt.

2. Do not remove the four 70 mm bolts as shown in figure 12.

1 70 mm – 3 (Do Not Remove) 2 70 mm –1 (Do Not Remove)

Figure 12 70 mm Bolts (Not To Be Removed)

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ACTIVITY 2.1 VALVE BODY REMOVAL (CONTINUED)

3. Remove the valve body from the case. Be careful not to lose the two vent check balls.

4. Why is it important that you do not remove the 70 mm bolts before removing the valve body from the case?

5. How is the solenoid harness removed?

TASK TWO: STRAINER AND 2ND BRAKE SEAL REMOVAL 1. Remove the strainer and 2nd brake retainer oil seal after removing the valve body.

Why is it important to remove the 2nd brake retainer oil seal at this time?

2. Is the second brake seal oriented?

Yes No

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ACTIVITY 2.1 VALVE BODY REMOVAL (CONTINUED)

TASK THREE: ACCUMULATOR REMOVAL 1. Remove the four accumulators.

2. Remove the accumulator springs.

3. How are the accumulator springs identified?

4. Which clutch or brake has only one accumulator spring?

a. L/R b. UD c. OD d. 2nd Brake

TASK FOUR: MANUAL LEVER REMOVAL 1. Remove the manual lever shaft pin.

2. Push the lever shaft up through the case.

3. Remove the two rubber O-rings from lever shaft. (fig. 13).

4. Remove the lever shaft.

Caution: When removing the park mechanism, the O-rings come off before removing the shaft to keep from getting a piece caught in the pinhole.

1 O-rings 3 Manual Lever 2 Retainer Pin

Figure 13 Manual Shaft O-rings

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SPEEDOMETER GEAR (2001 MODEL YEAR WITH VSS) The speedometer gear has a built-in vehicle speed sensor (fig. 14). Mechanically the speedometer gear on the F4A42 and F4A51 is different by the number of teeth on the gear. The F4A42 has 29/36 gear ratio while the F4A51 has a 28/36 gear ratio. Refer to Table 4.

Table 4 F4A42/F4A51 Gear Ratios

F4A42 F4A51 Speedometer Gear Ratio 29/36 28/36

1 Vehicle Speed Sensor Figure 14 Speedometer Gear

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OIL PUMP The F4A42 and F4A51 transaxles use the same oil pump. The oil pump is a rotor type pump consisting of a two-piece housing and a gear (fig. 15). If the pump fails, do not try to service it. Replace the assembly.

Caution: The oil pump is not serviceable; it must be replaced as a pump assembly. Do not disassemble the pump. Improper alignment during assembly causes pump failure and causes damage to the transaxle.

Figure 15 Oil Pump

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OIL FILTER The F4A42 and F4A51 transaxles use a non-woven type oil filter. The filter is located in the transaxle case (fig. 16). To service the oil filter the transaxle must be removed from the vehicle and the case halves split.

1 Main Oil Filter Figure 16 Oil Filter

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ACTIVITY 2.2 TRANSAXLE DISASSEMBLY

For this activity you will disassemble a F4A42 or F4A51 transaxle on the bench using the service manual.

TASK ONE: CASE SEPARATION 1. Remove the input/output speed sensors and VSS (if equipped), manual control

lever and the park/neutral position switch.

2. What is the measured input shaft endplay?

3. What is the input shaft endplay standard value (specification)?

4. Separate the converter housing and transaxle case.

5. What are the two O-rings located between the case halves used for?

6. Remove the differential assembly from the case.

TASK TWO: OIL FILTER, OIL PUMP AND INPUT SHAFT REMOVAL 1. Remove the oil filter.

2. Locate, identify and remove the oil pump.

3. What special tool number is used to remove the oil pump assembly?

4. Do not disassemble the oil pump.

Why is it important not to disassemble the oil pump?

5. Remove the input shaft, UD clutch and hub.

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ACTIVITY 2.2 TRANSAXLE DISASSEMBLY (CONTINUED)

TASK THREE: CLUTCH AND GEARTRAIN REMOVAL 1. Remove the rear cover.

2. What are the three O-rings located between the main transaxle case and rear cover used for?

3. Remove the reverse and overdrive clutches.

4. Remove the overdrive clutch hub.

5. Remove the planetary reverse sun gear.

6. Remove the 2nd brake and piston.

7. Remove the planetary carrier.

8. Remove the L/R brake and piston.

9. Remove the parking pawl.

10. Remove the transfer drive gear.

11. How is the transfer drive gear removed?

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ACTIVITY 2.2 TRANSAXLE DISASSEMBLY (CONTINUED)

TASK FOUR: OUTPUT SHAFT REMOVAL 1. Where is the output shaft nut located?

2. The output shaft nut is a left-handed thread.

True False

3. Can the nut be reused?

Yes No

4. How is the output shaft nut locked in place?

5. Remove the output shaft.

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Notes:

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Notes:

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CLUTCHES The input members of the planetary gear set in the F4A42 and F4A51 utilize three multi-disc clutches: the underdrive, overdrive and reverse clutch. Hydraulic fluid fills the piston pressure chamber (between the piston and retainer), moving the piston. In turn, the piston applies the clutch discs and transmits power from the retainer to the hub.

Underdrive Clutch The underdrive clutch operates in 1st, 2nd, and 3rd gears and transmits power from the input shaft to the underdrive sun gear. The underdrive clutch consists of the following (fig. 17):

• Input shaft • Snap rings (3) • D-rings (3) • Seal ring • Clutch reaction plate • Clutch discs (4) • Clutch plates (4) • Spring retainer • Return spring • Underdrive clutch piston • Underdrive clutch retainer

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1 D-ring 9 Clutch Plates 2 Return Spring 10 Seal Ring 3 Spring Retainer 11 Input Shaft 4 Snap Ring 12 Clutch Discs 5 D-ring 13 Underdrive Clutch Retainer 6 Snap Ring 14 D-ring 7 Selective Snap Ring 15 Underdrive Clutch Piston 8 Clutch Reaction Plate

Figure 17 Underdrive Clutch

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Reverse Clutch and Overdrive Clutch The reverse clutch operates when the reverse gear is selected, and transmits power from the input shaft to the reverse sun gear. The overdrive clutch operates in 3rd and 4th gears and transmits power from the input shaft to the overdrive planetary carrier and low/reverse annulus gear. The F4A42 and F4A51 use a different number of clutch plates in the overdrive clutch. Refer to Table 5. The reverse and overdrive clutch consists of the following (fig. 18):

• Snap rings (3) • D-rings (5) • Clutch reaction plates (2) • Clutch discs • Clutch plates • Spring retainer • Return spring • Reverse clutch piston • Overdrive clutch piston • Reverse clutch retainer

Table 5 Clutch Plates

Model Pressure Plate

Clutch Disc Clutch Plate

Clutch Reaction Plate

F4A42 4 4 1 Overdrive Clutch F4A51 1 4 3 1

Reverse Clutch 2 2 1

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1 Clutch Reaction Plate 11 Overdrive Clutch Piston 2 Clutch Plates 12 Return Spring 3 Clutch Plate (F4A42)

Pressure Plate (F4A51) 13 D-ring

4 Clutch Discs 14 Spring Retainer/Balance Piston 5 Reverse Clutch Retainer 15 Selective Snap Ring 6 D-ring 16 Clutch Discs 7 D-ring 17 Selective Snap Ring 8 D-ring 18 Clutch Reaction Plate 9 Reverse Clutch Piston 19 Clutch Plates 10 D-ring 20 Selective Snap Ring

Figure 18 Reverse Clutch and Overdrive Clutch

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Balance Pistons More responsive gear shifts at high engine speeds are achieved by two pressure-balanced pistons, one in the OD clutch and one in the UD clutch (fig. 19). The balance pistons replace the conventional ball check valve and are designed to cancel out centrifugal hydraulic pressure.

At high speeds, fluid remaining in the piston pressure chamber is subjected to centrifugal force and attempts to push the piston. However, fluid in the balance fluid chamber of the piston (the space between the piston and return spring retainer) is also subjected to centrifugal force. Therefore, the hydraulic pressure on one side of the piston cancels out the hydraulic pressure on the other side, and the piston does not move.

1 Retainer 5 Return Spring Retainer/Balance Piston

2 Piston 6 From Input Shaft 3 Piston Pressure Chamber 7 To Underdrive Sun Gear 4 Balance Fluid Chamber 8 Hub

Figure 19 Balance Piston

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BRAKES (HOLDING CLUTCHES) The holding members of the planetary gear set consist of two multi-disc clutches (low/reverse and second) referred to as brakes, and a one-way (over-running) clutch.

Low/Reverse Brake The low/reverse brake operates in 1st gear to provide additional holding power during takeoff, reverse gear, when the vehicle is parked, and during manual operation. It locks the low/reverse annulus gear and overdrive planetary carrier to the case. The low/reverse brake consists of two D-rings, brake discs and plates, pressure plate, return spring, spring retainer and a low/reverse brake piston (fig. 20).

The low/reverse brake is released by the PCM when a signal from the output shaft speed sensor is received. When there is no longer a signal, the PCM engages the low/reverse brake. This occurs at about 7 – 10 Km/h (4.4 – 6.2 mph).

1 Transmission Case 4 Second Brake 2 Rear Cushion Plate 5 Overdrive Planetary Carrier 3 Low/Reverse Brake 6 Reverse Sun Gear

Figure 20 Low/Reverse Brake

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Second Brake The second brake operates in 2nd and 4th gears and locks the reverse sun gear to the case (fig. 21). The second brake consists of two D-rings, a second brake piston and second brake retainer.

1 Transmission Case 4 Second Brake 2 Rear Cushion Plate 5 Overdrive Planetary Carrier 3 Low/Reverse Brake 6 Reverse Sun Gear

Figure 21 Second Brake Operation

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One-Way Clutch The one-way clutch is a mechanical holding device consisting of an outer race (part of the L/R annulus gear), a fixed inner race, and sprags (fig. 22). It holds in 1st gear to prevent counterclockwise rotation of the L/R annulus viewed from the front of the transaxle. When the L/R brake is applied, it holds the L/R annulus and stops it from rotating in both directions.

The one-way clutch prevents engine flare, improving the quality of the 1st to 2nd upshift, and also assists in a smoother coasting downshift. When installing the one-way clutch, the arrow is installed pointing towards the output planetary carrier. The F4A42 and F4A51 transaxles use a one-way clutch.

1 Low/Reverse Brake 7 Reverse Sun Gear 2 One-Way Clutch 8 Input Shaft 3 Underdrive Clutch 9 Overdrive Clutch 4 Output Planetary Carrier 10 Reverse Clutch 5 Underdrive Sun Gear 11 2nd Brake 6 Low/Reverse Annulus Gear

Figure 22 One-Way Clutch

37


PLANETARY GEAR SETS The planetary gear set assembly contains two planetary gear sets as follows (fig. 23):

• Snap rings (2) • Planetary reverse sun gear • Overdrive planetary carrier • Underdrive sun gear • Output planetary carrier

The carrier of one gear set is connected mechanically to the annulus gear of the other. This arrangement allows the gear ratio to be varied by connecting or locking the carriers and sun gears.

Note: Apply automatic transmission fluid to all moving parts before installation.

1 Underdrive Sun Gear 7 Thrust Bearing No. 3 2 Planetary Reverse Sun Gear 8 One-Way Clutch 3 Snap Ring 9 Stopper Plate 4 Overdrive Planetary Carrier 10 Snap Ring 5 L/R Annulus Gear 11 Output Planetary Carrier 6 Thrust Bearing No. 4

Figure 23 Planetary Gear Sets

38


DIFFERENTIAL Taper roller bearings are used on either side of the differential (fig. 24). Differential case preload is calculated by removing the differential bearing outer race from the torque converter housing, placing two beads of solder on the torque converter housing and reinstalling the differential bearing outer race and torque converter housing. Measure the solder and add the reading to the selected shim.

1 Selective Spacer 6 Selective Washers 2 Taper Roller Bearings 7 Differential Case 3 Differential Drive Gear 8 Pinion Shaft 4 Side Gears 9 Lock Pin 5 Pinion Gears 10 Bolts (8)

Figure 24 Differential

39


Transfer Drive Gear The transfer drive gear is located in the center of the transaxle (fig. 25). The bearing supporting the drive gear is a pre-loaded type and is bolted directly onto the case.

When installing the transfer drive gear in the transaxle case a special tool (MD998412) is used as a guide to help locate the transfer drive gear bearing in the transaxle case. There are seven mounting bolts on the F4A42 and eight mounting bolts on the F4A51. The mounting bolts are tightened to a specified torque.

Figure 25 Transfer Drive Gear

40


Output Shaft/Transfer Driven Gear The transfer driven gear is press-fitted onto the output shaft, and the output shaft is secured by a locknut and supported by bearings (fig. 26). The locknut has a left-handed thread, and is secured to the output shaft by staking. A 19 mm hexagonal hole in the other end of the shaft enables the shaft to be held in position for locknut removal.

1 Bearing Retainer 4 Output Shaft 2 Transfer Driven Gear 5 Taper Rolling Bearing 3 Outer Race

Figure 26 Output Shaft/Transfer Driven Gear

Note: Use new lock nut when reassembling.

41


MODULE 3 POWERFLOW

PARK AND NEUTRAL In park and neutral, all input clutches are disengaged and no power from the input shaft is transmitted to the planetary gears (fig. 27). The low/reverse brake is applied, and it holds the low/reverse annulus gear, enabling a quick shift to 1st gear or reverse.

1 Low/Reverse Brake 8 Output Annulus Gear 2 Output Pinion 9 Overdrive Pinion Gear 3 Underdrive Clutch 10 Reverse Sun Gear 4 Input Shaft 11 Overdrive Planetary Carrier 5 Output Planetary Carrier 12 Overdrive Clutch 6 Underdrive Sun Gear 13 Reverse Clutch 7 Low/Reverse Annulus Gear 14 2nd Brake

Figure 27 Park and Neutral

42


REVERSE In reverse, the reverse clutch and low/reverse brake are applied (fig. 28). Power from the input shaft is transmitted to the reverse sun gear through the reverse clutch. The low/reverse brake locks the overdrive planetary drive carrier, transmitting the power of the reverse sun gear to the output annulus gear as counter clockwise torque. Torque is transmitted to the output planetary carrier, achieving reverse gear ratio.


Figure 28 Reverse

43


FIRST GEAR In 1st gear, the underdrive clutch and low/reverse brake are applied (fig. 29). Power is transmitted from the input shaft to the underdrive sun gear through the underdrive clutch. The output pinions rotate around the underdrive sun gear causing the output planetary carrier to turn clockwise. Since the low/reverse brake is applied and the low/reverse annulus gear is locked, only the output planetary carrier turns clockwise achieving 1st gear. Above 6 mph the overrun clutch holds the low/reverse annulus because the low/reverse brake is released.


Figure 29 First Gear

44


SECOND GEAR In 2nd gear, the underdrive clutch and second brake are applied (fig. 30). When the transmission shifts from 1st gear to 2nd gear, the second brake is applied. When the reverse sun gear is locked, power from the output annulus gear causes the overdrive pinions to rotate around the reverse sun gear, turning the overdrive planetary carrier clockwise.

The output planetary carrier is linked to the output annulus gear, driving the overdrive pinion gears. The overdrive planetary carrier is linked to the low/reverse annulus gear turning the reverse annulus gear clockwise. The rotation of the low/reverse annulus gear is added to the 1st gear rotation of the output planetary carrier, achieving 2nd gear ratio.


Figure 30 Second Gear

45


THIRD GEAR In 3rd gear, the underdrive clutch and overdrive clutch are applied (fig. 31). The overdrive clutch connects the input shaft to the overdrive planetary carrier and low/reverse annulus gear. This causes the underdrive sun gear and low/reverse annulus gear to rotate at the same speed, while the planetary gear set rotates as a single, locked unit achieving 3rd gear ratio.


Figure 31 Third Gear

46


FOURTH GEAR In 4th gear, the overdrive clutch and second brake are applied (fig. 32). Power from the input shaft is transmitted to the overdrive planetary carrier through the overdrive clutch. The reverse sun gear is locked by the second brake. The overdrive pinions rotate around the reverse sun gear transmitting power to the output planetary carrier, achieving 4th gear ratio.


Figure 32 Fourth Gear

47


ACTIVITY 3.1 PLANETARY CARRIER

1. Assemble the planetary carrier.

2. Are the Torrington bearings directional?

Yes No

3. When assembling the planetary carrier and installing the overrunning clutch/one-way clutch, which direction should the arrows point?

4. What are the notches on the overrunning clutch inner race used for?

48


ACTIVITY 3.1 (CONTINUED) APPLIED MEMBERS: WHAT’S ON WHEN (WOW)

CLUTCH AND GEARTRAIN Use the Service Manual hydraulic schematics to determine which clutches and brakes are applied during each of the following gears.

Shift Lever Position

Applied Input Clutch

Driven Planetary Member

Applied Holding Brake

Held Planetary Member

P-Park L/R Annulus

R-Reverse

Reverse Sun Gear

L/R Annulus

N-Neutral L/R Annulus

D-Overdrive First

Underdrive Sun Gear

L/R Annulus

Second Underdrive Sun Gear

Reverse Sun Gear

Overdrive Carrier

Third

Underdrive Sun

Gear

Fourth Overdrive Carrier

Reverse Sun Gear

49


ACTIVITY 3.2 GEAR RATIOS

1. Set up the planetary gear set in a pair of V-blocks.

2. Mark the input and output elements with a colored paint pen.

3. Rotate the driven planetary member while holding the corresponding held planetary member and count the number of turns it takes to rotate the output shaft one complete turn of the input member for each gear.

4. Record the number of turns and the gear ratio in the chart below.

Gear Driven Member

Held Member

Turn Input Turns

F4A42-----F4A51

Turn Output Turns

Gear Ratio

F4A42-------F4A51

1st

2nd

3rd

4th

R

5. Do the gear ratios match those on page 5 in student workbook?

6. What is the benefit of knowing clutch application and gear ratios?

50


ACTIVITY 3.3 TRANSAXLE ASSEMBLY

TASK ONE: TRANSFER GEAR INSTALLATION 1. Install the transfer gear.

2. What special tool is needed to install the transfer gear?

TASK TWO: L/R AND 2ND BRAKE SET-UP Note: Leave out the adjustment plate for both the LR and 2nd brake adjustment procedure

1. What is the purpose of the tab on the L/R brake piston?

2. Why is it critical to line up the one-way clutch inner race identification notches with the centerline of the transmission?

3. Assemble the L/R and 2nd brake. Measure and record the clearances below.

4. There are three adjustments critical to proper L/R and 2nd brake adjustment. What are the adjustments?

51


ACTIVITY 3.3 TRANSAXLE ASSEMBLY (CONTINUED)

5. What component is used to set the clearance for the L/R and 2nd brake clearance?

6. When checking the L/R and 2nd brake clearances special tools are used to check clutch clearance. How are they different between an F4A42 and an F4A51?

7. When installing the L/R and 2nd brake reaction plate, what is the proper orientation for the plate?

8. What is the tab on the 2nd brake piston used for?

52



TASK THREE: OUTPUT SHAFT INSTALLATION AND SETUP 1. Install the output shaft using the thinnest shim (0.074 inch (1.88 mm)).

2. Measure the output shaft end play and record

3. Add 0.074 (1.88 mm) and 0.0004-0.0035 (0.01-0.09 mm) to the measurement recorded above.

4. What does this measurement give you?

5. Using the correct shim, install the output shaft assembly.

6. Can the mounting bolts be reused? Why?

7. Can the staked nut be reused? Why?

53



TASK FOUR: PARKING PAWL INSTALLATION 1. Install the parking pawl assembly.

2. How many pins are used to hold it in?

3. What should you do if you have trouble installing the parking pawl pins?

TASK FIVE: PLANETARY CARRIER INSTALLATION 1. Install the planetary carrier.

2. Install the reverse sun gear.

3. Remove the bearing from the rear cover and inspect for wear.

4. Install the bearing in the rear cover and install the rear cover.

5. What special tool is used to service the rear cover bearing?

6. Thrust washer (race) No. 8 is a selective thrust washer. How would you find the correct thickness thrust washer for the underdrive sun gear?

54



TASK SIX: UNDERDRIVE AND OVERDRIVE/REVERSE CLUTCH SETUP 1. When assembling the reverse clutch piston and retainer, what is the proper

orientation during installation?

2. There is a clearance check for the reverse clutch retainer snap ring. Where is the clearance check made?

3. Which bearing rides against a selectable surface?

4. Which two bearings are installed opposite to all others?

5. Where does the number two bearing fit in the transmission?

6. If the number two (or any) thrust bearing is installed backwards, what would happen?

7. Why do the underdrive and overdrive clutches use a balance piston?

55



8. Which component is used to adjust the underdrive/overdrive and reverse clutch clearance?

9. Which pressure plates are directional and why?

TASK SEVEN: OIL PUMP INSTALLATION 1. How is input shaft endplay measured?

2. Install the oil pump. Measure and record the input shaft endplay.

3. What is the recorded measurement used for?

TASK EIGHT: CONVERTER HOUSING INSTALLATION Note: Remember to install the oil filter before attaching the torque converter housing.

1. Are there any measurements needed when installing the converter housing?

56



2. How is differential preload measured?

1 Converter Housing Short Bolts

Fig 33. Converter Short Bolt Locations

3. Record the measurement

4. Add 0.0018-0.0041 (0.045 mm-0.105 mm) to the measured value then select a spacer with the corresponding thickness.

5. What does this measurement give you?

57


MODULE 4 VALVE BODY/HYDRAULIC CONTROL SYSTEM

The following components are all housed in the valve body (fig. 34):

• Four solenoid valves to clutches (which convert PCM signals to hydraulic pressure) • Four pressure control valves to clutches (which control hydraulic pressure to the clutches and brakes) • Check balls • Regulator valve (which maintains the hydraulic pressure at a constant level) • Converter pressure control valve • One Damper clutch control valve • One Damper clutch solenoid valve • Manual valve • Switch valve • Fail-safe valve A • Fail-safe valve B

58


1 Torque Converter Valve 11 Low/Reverse Pressure Control Valve

2 Fail-Safe Valve B 12 Overdrive Pressure Control Valve 3 Plate 13 Solenoid Valve 4 Outside Valve Body Assembly 14 Solenoid Valve Support 5 Underdrive Pressure Control Valve 15 Fail-Safe Valve A 6 Solenoid Valve Support 16 Regulator Valve Assembly 7 Solenoid Valve 17 Torque Converter Clutch Control

Valve 8 2nd Pressure Control Valve 18 Manual Valve 9 Valve Body Cover 19 Plate 10 Switching Valve 20 Inside Valve Body Assembly

Figure 34 Valve Body Components

59


CHECK BALLS To prevent the escape of ATF from the valve body, clutches, and brakes (when the engine is not running), the valve drainage ports are connected to a single drainage port located at a high point on the casing with a ball check valve fitted at the end of the drainage line. In the event of an electronic control system fault, a switch valve and fail-safe valve arrangement enables operation in 3rd gear or reverse. There are two steel balls located on the valve body near the manual valve (fig. 35). These balls act as check valves to allow fluid to pass in one direction and to prevent air from entering the fluid from the opposite direction.

1 Check Balls Figure 35 Valve Body Ball Check Valves

60


Each solenoid valve has a check ball (five in total) that moves off its seat when the solenoid is OFF, allowing fluid pressure to apply the clutches and brakes (fig. 36). When the solenoid is duty cycled (ON) the check ball returns to its seat and fluid pressure is blocked to the clutches and brakes turning them off.

1 Solenoid Valve Check Ball Figure 36 Solenoid Valve Check Ball

61


PRESSURE CONTROL VALVES AND SOLENOID VALVES Except for the reverse clutch, there is one pressure control valve and one solenoid valve for each clutch and brake. Under the control of the solenoid valves, the pressure control valves regulate the hydraulic pressure against the elements to prevent the occurrence of harsh application during gear shifts. Refer to Table 6. The solenoid valves are duty-cycled by signals from the PCM.

Table 6 Solenoid Control Valve Operation Chart

Solenoid Valves

Gear L/R 2ND UD OD DCC (REF.)1ST OFF* ON OFF ON OFF

2ND ON OFF OFF ON ON

3RD ON ON OFF OFF ON

4TH ON OFF ON OFF ON

Reverse OFF ON ON ON OFF

N-P OFF ON ON ON OFF * At 6 mph the solenoid turns on leaving the one way clutch on.

Operation When the solenoid valve is ON and the fluid passage from the solenoid valve is closed, there is no hydraulic pressure to the pressure control valve. At this time, the pressure control valve is pushed toward the right by the force of its spring, closing off the port, and no hydraulic pressure is supplied to the clutch.

When the solenoid valve is OFF, the fluid passage from the solenoid valve is open, supplying hydraulic pressure to the pressure control valve. Hydraulic pressure overcomes the spring pressure in the pressure control valve causing it to compress the spring, which opens a port and allows the line pressure to be supplied to the clutch.

62


REGULATOR VALVE The pressure regulator valve maintains hydraulic pressure from the oil pump at a specified line pressure, depending on transaxle range (fig. 37). As line pressure to the valve overcomes spring pressure, the valve moves and allows fluid pressure to the clutches to be adjusted.

1 Regulator Valve 4 Oil Pump 2 Manual Control Valve 5 Oil Pan 3 Relief Valve 6 Oil Filter

Figure 37 Regulator Valve

63


TORQUE CONVERTER PRESSURE CONTROL VALVE The torque converter pressure control valve maintains a constant fluid pressure to the torque converter to disengage the damper clutch and provide lubricating pressure (fig. 38). Surplus fluid after adjustment of the line pressure by the regulator valve is supplied to the torque converter by the torque converter pressure control valve. As line pressure to the torque converter pressure control valve increases and overcomes spring pressure, the valve moves venting pressure, which allows torque converter fluid pressure to be constantly regulated.

Notes:

64


1 Torque Converter Clutch Apply 5 Torque Converter Pressure Control Valve Regulator Valve

2 Torque Converter Clutch Release 6 Oil Pump 3 Torque Converter Clutch Control

Valve 7 Oil Filter

4 Torque Converter Clutch Solenoid Valve

8 Oil Pan

Figure 38 Torque Converter Pressure Control Valve

65


DAMPER CLUTCH CONTROL VALVE AND DAMPER CLUTCH SOLENOID VALVE The damper clutch solenoid valve controls the hydraulic pressure supplied to the damper clutch control valve and damper clutch. The damper clutch solenoid valve is duty-cycled by the PCM converting electric signals into hydraulic pressure.

Operation When the damper clutch solenoid valve is OFF, hydraulic and spring pressure move the valve to the right, allowing hydraulic pressure through the line to the space between the torque converters front cover and damper clutch. This causes the damper clutch to disengage and the torque converter to work normally (fig. 39). When the damper clutch solenoid is duty cycled, the hydraulic pressure is reduced which allows spring pressure to move the valve to the left and line pressure to enter the torque converter. The damper clutch is pressed against the front cover and the damper clutch operates (fig. 40).

1 Apply Pressure (50 psi) 5 To Manual Control Valve 2 Release Pressure (75 psi) 6 To Torque Converter Pressure

Control Valve 3 Torque Converter Clutch Control

Valve 7 To Cooler

4 To Torque Converter Clutch Solenoid Valve

8 To Torque Converter Clutch Solenoid Valve

Fluid Exhaust Restrictor

Figure 39 Damper Clutch Control Valve Operation (Off)

66


1 2nd Brake 11 Manual Valve 2 OD Clutch 12 Regulator Valve 3 Accumulator 13 Relief Valve 4 Fail-Safe Valve B 14 Oil Pump 5 Fail-Safe Valve A 15 Oil Pan 6 Switch Valve 16 Oil Filter 7 2nd Pressure Control Valve 17 Torque Converter Pressure Control

Valve 8 2nd Solenoid Valve 18 Torque Converter Clutch Solenoid

Valve 9 OD Pressure Control Valve 19 Torque Converter Clutch Control

Valve 10 OD Solenoid Valve 20 Torque Converter Clutch

One-Way Check Ball Restrictor

Fluid Exhaust

Pressure Tap Figure 40 Damper Clutch Operation (On)

67


HYDRAULIC OPERATION

In park and neutral, all of the clutches are released. To enable a quick shift to 1st gear or reverse, the L/R brake is applied. The manual valve directs hydraulic pressure to the regulator valve, which lowers line pressure to soften gear engagement when a shift selection is made (fig. 41).

Notes:

Park and Neutral

68


1 L/R Brake 8 Relief Valve 2 Fail-Safe Valve A 9 Oil Pump 3 Fail-Safe Valve B 10 Oil Pan 4 Switch Valve 11 Oil Filter 5 L/R Solenoid Valve 12 Torque Converter Pressure Control

Valve 6 Manual Valve 13 L/R Pressure Control Valve 7 Regulator Valve 14 Accumulator

One-Way Check Ball

Restrictor

Fluid Exhaust

Pressure Tap Figure 41 Hydraulic Circuit (Park/Neutral)

69


Reverse In reverse, the reverse clutch and L/R brake are applied. When the shift lever is moved to the R position, line pressure goes directly to the reverse clutch through the manual control valve. The PCM de-energizes the L/R solenoid valve, which allows line pressure to move the L/R pressure control valve. The movement of the control valve allows line pressure through fail-safe valve A to apply the L/R brake (fig. 42).

Notes:

70


1 L/R Brake 9 Oil Pump 2 Fail-Safe Valve A 10 Oil Pan 3 Fail-Safe Valve B 11 Oil Filter 4 Switch Valve 12 Torque Converter Pressure Control

Valve 5 L/R Solenoid Valve 13 L/R Pressure Control Valve 6 Manual Valve 14 Torque Converter Clutch Control

Valve 7 Regulator Valve 15 Accumulator 8 Relief Valve 16 Reverse Clutch

One-Way Check Ball

Restrictor

Fluid Exhaust

Pressure Tap Figure 42 Hydraulic Circuit (Reverse)

71


First Gear In first gear the manual valve directs line pressure to all of the solenoid valves. The UD solenoid valve is de-energized, which allows line pressure to actuate the UD pressure control valve and send line pressure to the UD clutch. The L/R solenoid valve is also de-energized, allowing line pressure to actuate the L/R pressure control valve, forcing line pressure through fail-safe valve A to apply the L/R brake. The L/R solenoid valve is energized to release the L/R brake at approximately 6 mph and the one-way clutch continues to hold (fig. 43).

Notes:

72


1 L/R Brake 11 Regulator Valve 2 Fail-Safe Valve A 12 Relief Valve 3 Accumulator 13 Oil Pump 4 UD Clutch 14 Oil Pan 5 Fail-Safe Valve B 15 Oil Filter 6 Switch Valve 16 Torque Converter Pressure Control

Valve 7 L/R Solenoid Valve 17 L/R Pressure Control Valve 8 UD Pressure Control Valve 18 Torque Converter Clutch Solenoid

Valve 9 UD Solenoid Valve 19 Torque Converter Clutch Control

Valve 10 Manual Valve

One-Way Check Ball

Restrictor

Fluid Exhaust

Pressure Tap Figure 43 Hydraulic Circuit (1st)

73


Second Gear When the transaxle shifts from 1st to 2nd gear, the L/R brake is released and the 2nd brake is applied. When releasing the L/R brake, the PCM energizes the L/R solenoid valve, which shuts off line pressure to the L/R pressure control valve, which shuts off line pressure to the L/R brake. The 2nd brake is engaged when the PCM de-energizes the 2nd solenoid valve and the 2nd pressure control valve moves to allow line pressure through fail-safe valve B to apply the brake (fig. 44).

Notes:

74


1 2nd Brake 11 Manual Valve 2 Fail-Safe Valve A 12 Regulator Valve 3 Accumulator 13 Relief Valve 4 UD Clutch 14 Oil Pump 5 Fail-Safe Valve B 15 Oil Pan 6 Switch Valve 16 Oil Filter 7 2nd Pressure Control Valve 17 Torque Converter Pressure Control


Valve 9 UD Pressure Control Valve 19 Torque Converter Clutch Control

Valve 10 UD Solenoid Valve 20 Torque Converter Clutch

One-Way Check Ball

Restrictor

Fluid Exhaust

Pressure Tap

Figure 44 Hydraulic Circuit (2nd)

75


Third Gear When the transaxle shifts from 2nd to 3rd gear, the 2nd brake is released and the OD clutch applied. The PCM energizes the 2nd solenoid valve and the 2nd pressure control valve moves to block the pressure through fail-safe valve B, releasing the 2nd brake. The PCM de-energizes the OD pressure control valve, which opens the line pressure passage and applies the OD clutch (fig. 45).

Notes:

76


1 Fail-Safe Valve A 13 OD Solenoid Valve 2 UD Clutch 14 Manual Valve 3 Accumulator 15 Regulator Valve 4 OD Clutch 16 Relief Valve 5 Fail-Safe Valve B 17 Oil Pump 6 Switch Valve 18 Oil Pan 7 L/R Solenoid Valve 19 Oil Filter 8 2nd Pressure Control Valve 20 Torque Converter Pressure Control

Valve 9 2nd Solenoid Valve 21 L/R Pressure Control Valve 10 UD Pressure Control Valve 22 Torque Converter Clutch Solenoid


Valve 12 OD Pressure Control Valve 24 Torque Converter Clutch

One-Way Check Ball

Restrictor

Fluid Exhaust

Pressure Tap Figure 45 Hydraulic Circuit (3rd)

77


Fourth Gear When the transaxle shifts from 3rd to 4th gear, the UD clutch is released and the 2nd brake is applied. The UD clutch is released when the PCM energizes the UD solenoid valve, which exhausts line pressure to the UD pressure control valve blocking line pressure to the UD clutch. The 2nd brake is applied when the PCM de-energizes the 2nd solenoid valve and the 2nd pressure control valve moves to allow line pressure through fail-safe valve B to apply the brake (fig. 46).

Notes:

78






One-Way Check Ball

Restrictor

Fluid Exhaust

Pressure Tap Figure 46 Hydraulic Circuit (4th)

79


MANUAL VALVE The manual valve is linked to the gear selector lever. As the selector lever is moved, the manual valve switches fluid from one passage to another, feeding line pressure to the proper valves. While there are seven selector positions on the range indicator, the manual valve actually has only three positions, R (Reverse), P/N (Park/Neutral), and D (Low, 2nd, 3rd, and Drive).

Operation (P/N) With the manual valve in the P/N position, line pressure is fed to the regulator valve and fail-safe valve A (fig. 47).

Notes:

80


1 L/R Brake 8 Relief Valve 2 Fail-Safe Valve A 9 Oil Pump 3 Fail-Safe Valve B 10 Oil Pan 4 Switch Valve 11 Oil Filter 5 L/R Solenoid Valve 12 Torque Converter Pressure Control

Valve 6 Manual Valve 13 L/R Pressure Control Valve 7 Regulator Valve 14 Accumulator

One-Way Check Ball

Restrictor

Fluid Exhaust

Pressure Tap Figure 47 Manual Valve (P/N)

81


Operation (R) In reverse, the reverse clutch and L/R brake are applied. When the shift lever is moved to the R position, line pressure goes directly to the reverse clutch through the manual control valve. The PCM de-energizes the L/R solenoid valve, which allows line pressure to move the L/R pressure control valve. The movement of the control valve allows line pressure through fail-safe valve A to apply the L/R brake (fig. 48).

Notes:

82


1 L/R Brake 9 Oil Pump 2 Fail-Safe Valve A 10 Oil Pan 3 Fail-Safe Valve B 11 Oil Filter 4 Switch Valve 12 Torque Converter Pressure Control

Valve 5 L/R Solenoid Valve 13 L/R Pressure Control Valve 6 Manual Valve 14 Torque Converter Clutch Control

Valve 7 Regulator Valve 15 Accumulator 8 Relief Valve 16 Reverse Clutch

One-Way Check Ball

Restrictor

Fluid Exhaust

Pressure Tap Figure 48 Manual Valve (R)

83


Operation (D) With the manual valve in the D position line pressure is fed to the 2nd brake, UD clutch and OD clutch solenoid valves, and to the relevant pressure control valves (fig. 49).

Notes:

84






One-Way Check Ball

Restrictor

Fluid Exhaust

Pressure Tap Figure 49 Manual Valve (D)

85


SWITCH VALVE When the OD clutch operates, hydraulic pressure from the switch valve is supplied to the regulator valve. The switch valve inhibits the connection of the L/R brake when the solenoid is off during limp-in operation. It also is used to reduce the hydraulic pressure in 3rd and 4th gears. In 1st, 2nd, and reverse gears, line pressure pushes the valve to the left, directing pressure to fail-safe valve A. In a limp-in condition, when the control relay is off, line pressure pushes the valve to the right. As a result, hydraulic pressure to fail safe valve A is cut off, blocking pressure to the L/R brake. In 3rd and 4th gears, hydraulic pressure is supplied to the valve, pushing it to the right. As a result, hydraulic pressure is supplied to the regulator valve, reducing the line pressure (fig. 50).

Notes:

86






One-Way Check Ball

Restrictor

Fluid Exhaust

Pressure Tap Figure 50 Switch Valve (OD On)

87


When the control relay is OFF and the limp-in (fail-safe) mechanism operates, the supply of hydraulic pressure from the L/R pressure control valve to the L/R brake is released through the switch valve (fig. 51).

Notes:

88


1 Fail-Safe Valve A 13 OD Solenoid Valve 2 UD Clutch 14 Manual Valve 3 Accumulator 15 Regulator Valve 4 OD Clutch 16 Relief Valve 5 Fail-Safe Valve B 17 Oil Pump 6 Switch Valve 18 Oil Pan 7 L/R Solenoid Valve 19 Oil Filter 8 2nd Pressure Control Valve 20 Torque Converter Pressure Control




One-Way Check Ball

Restrictor

Fluid Exhaust

Pressure Tap Figure 51 Switch Valve (Fail-Safe)

89


FAIL-SAFE VALVE A When the vehicle is traveling forward, fail-safe valve A releases the L/R brake hydraulic pressure in the event of a limp-in condition. In reverse, fail-safe valve A changes the fluid passage to the L/R brake and thus achieves quick, smooth gear shifts.

FAIL-SAFE VALVE B In the event of a limp-in condition (when the control relay is OFF), fail-safe valve B cuts the supply of hydraulic pressure from the 2nd pressure control valve to the 2nd brake.

In major limp-in all of the solenoid valves are off. Fail-safe valve A and B are utilized to inhibit application of the L/R and 2nd brakes. The result is 3rd gear only in forward travel.

Notes:

90


ACTIVITY 4.1 VALVE BODY DISASSEMBLY

For this activity you will disassemble the valve body and identify the following components:

• Check ball location • Solenoids (mark location) • Valve locations

1. What is the purpose of the two check balls located on the valve body near the

manual valve?

2. If the gear selector is moved from OD through low gear, and the manual valve does not move, how does the transmission know which gear the driver has selected?

3. How much does each complete turn of the line pressure adjusting screw change the pressure?

4. Which way is the line pressure adjusting screw turned to increase line pressure?

91


ACTIVITY 4.2 HYDRAULIC OPERATION

Use the Service Manual hydraulic schematics to determine the operating gear for the hydraulic path and applied clutches and solenoids identified in the following worksheet (sample shown for “D-overdrive”).

Operating Gear

Applied Turning Clutch


Energized Solenoids

De-energized Solenoids

D-Overdrive First (under 6 mph)

Line pressure through manual valve, de-energized UD solenoid valve, UD pressure control valve, applies UD clutch

Line pressure through manual valve, de-energized L/R solenoid valve, L/R pressure control valve, switch valve, fail-safe valve A, applies L/R brake, over running clutch applied

2nd - to block

OD - to block

L/R - to apply

UD - to apply

No applied turning clutch

Line pressure through manual valve, de-energized L/R solenoid valve, L/R pressure control valve, switch valve and fail-safe valve A, applies L/R brake

2nd – to block

UD - to block

OD – to block

L/R – to apply


Line pressure through manual valve, de-energized L/R solenoid valve, L/R pressure control valve, switch valve, fail-safe valve A, applies L/R brake, over running clutch applied

2nd - to block

OD - to block

L/R - to apply

UD - to apply

Line pressure through manual control valve, UD solenoid valve and UD pressure control valve, applies UD clutch

Line pressure through manual valve, through de-energized 2nd solenoid valve, 2nd pressure control valve and fail-safe valve B, applies 2nd brake

L/R – to block

OD – to block

DCC – to apply

UD - to apply

2nd – to apply

92


ACTIVITY 4.2 (CONTINUED) HYDRAULIC OPERATION

Operating Gear



Energized Solenoids

De-energizedSolenoids

No applied turning clutch


2nd – to block

UD - to block

OD – to block

L/R – to apply


Line pressure through manual valve, blocked at L/R solenoid valve, releases L/R brake, over running clutch applied

2nd - to block

OD - to block

L/R – to block

UD - to apply

Line pressure through manual valve applies reverse clutch


UD - to block

DCC

2nd – to block

OD – to block

L/R - to apply

Line pressure through manual valve, OD solenoid valve, OD pressure control valve, applies OD clutch

Line pressure through manual valve, de-energized 2nd solenoid valve, 2nd pressure control valve, applies 2nd brake

UD - to block

L/R – to block

DCC

2nd – to apply

OD – to apply

93


ACTIVITY 4.2 (CONTINUED) HYDRAULIC OPERATION

Operating Gear



Energized Solenoids

De-energized Solenoids

Line pressure through manual valve, de-energized UD solenoid valve, de-energized OD solenoid valve, UD pressure control valve, OD pressure control valve, applies UD and OD clutches

No applied holding brake

No energized solenoids

UD – to apply

2nd – to apply

L/R – to apply

OD – to apply

Line pressure through manual valve, de-energized UD solenoid valve, de-energized OD solenoid valve, UD pressure control valve, OD pressure control valve applies UD and OD clutches

No applied holding brake

L/R – to block

2nd – to block

DCC

UD – to apply

OD – to apply

Line pressure through manual valve applies reverse clutch


UD – to apply

2nd – to apply

L/R – to apply

OD – to apply

94


Notes:

95


Notes:

96


MODULE 5 ELECTRONIC CONTROL SYSTEM

This module covers the following electronic components:

ELECTRONIC COMPONENTS • Input and Output Speed Sensors • Crankshaft Position Sensor • Throttle Position Sensor • A/T Fluid Temperature Sensor • Park/Neutral Position Switch • Vehicle Speed Sensor (2001 Model Year Only) • A/C Dual Pressure Switch • Stoplight Switch • Solenoids • A/T Control (ECC) Relay

The Autostick automatic transaxle is another innovation of DaimlerChrysler Corporation’s automatic transaxle. This new system allows for significantly easier driving under any road and driving conditions. Also, the Autostick automatic transaxle features a 4-position (P, R, N, D) selector lever and does not require the conventional OD OFF switch.

The clutches and brakes have dedicated solenoid valves. This enables each clutch and brake to be controlled independently and directly with a system of "clutch-to-clutch" control.

97


POWERTRAIN CONTROL MODULE (PCM) The system management is carried out by the Powertrain Control Module (PCM), which is a combination of the Engine Control Unit (ECU) and the A/T-ECU. The control signals are input or output through a 130-pin connector having the following circuit arrangement (fig. 52).

The PCM controls transaxle operation by monitoring sensor inputs, and analyzing the information. Then it controls shift timing, shift quality, and damper clutch operation using a transaxle control relay and solenoid valves. The PCM is mounted against the bulkhead behind the glove box under the instrument panel (fig. 53).

Figure 52 PCM Connector (Front View)

1 Instrument Panel 2 PCM Figure 53 PCM Location

98


PCM CONNECTOR PIN FUNCTION PIN FUNCTION 1-35 Engine use 101 Park/Neutral position switch P130:

overdrive solenoid valve 41-44 Engine use 102 Park/Neutral position switch D 45 Crankshaft position sensor 103 Input shaft speed sensor 46 Throttle position sensor power

supply 104 Output shaft speed sensor

47-49 Engine use 105 1st gear shift indicator light (vehicles with Autostick)

50 A/T control relay 106 Second solenoid valve 51-56 Engine use 107 Torque converter clutch solenoid valve 57 Sensor ground 108 Park/Neutral position switch R 58-65 Engine use 109 Park/Neutral position switch 3

(vehicles without Autostick), select switch

66 Back-up power supply 110 Park/Neutral position switch L (vehicles without Autostick)

71-74 Engine use 111 Immobilizer system 75 Auto-cruise control unit 112 76 Ground 113 Diagnostic output 77 Solenoid valve power supply 114 78 Throttle position sensor 115 79 Auto-cruise control unit 116 80 Diagnostic output

(VSS on 2001 Model Year only) 117 3rd gear shift indicator light (vehicles

with Autostick) 81-82 Engine use 118 2nd gear shift indicator light (vehicles

with Autostick) 83 Air conditioning compressor load

signal 119

84 Diagnostic control 120 Underdrive solenoid valve 85 Diagnostic output 121 Park/Neutral position switch N 86 122 Park/Neutral position switch 2

(vehicles without Autostick), shift switch (up) (vehicles with Autostick)

87 123 Stop light switch 88 Ground 124 A/T fluid temperature sensor 89 Solenoid valve power supply 125 90-94 Engine use 126 95 127 96 Low fuel level warning light 128 4th gear shift indicator light (vehicles

with Autostick) 97 Ground 129 Low/reverse solenoid valve 98 Engine use 130 Overdrive solenoid valve

99


SYSTEM CONSTRUCTION DIAGRAM

Powertrain Control Module (PCM)

Ignition switch

<

Damper clutch control

Self-diagnosis control

N-range lamp control

Gear shift hydraulic control

Shift control pattern

100

Limp-in operation (N range light flashing)

vehicle with Autostick>

Second solenoid valve

Low/Reverse solenoid valve

Torque converter clutch solenoid valve

A/T control relay
Shift switch (up, down)
<vehicles with Autostick>

Select switch <vehicles with Autostick>

Cruise control unit (OD OFF signal)

Brake switch

Dual pressure switch

VSS (2001 only)

Park/Neutral position switch

A/T fluid temperature sensor

Throttle position sensor

Crankshaft position sensor

Output shaft speed sensor

Input shaft speed sensor

Diagnosis trouble code output (N range light

flashing) <vehicle with Autostick>

Overdrive solenoid valve

Underdrive solenoid valve

DRBIII

INPUTS
OUTPUTS
Serial communication


SENSORS AND ACTUATORS Item Function


Detects when input shaft speed = turbine speed at UD clutch retainer


Detects when output shaft speed = transfer drive gear speed at transfer driven gear

Crankshaft position sensor

Detects engine speed at crankshaft sprocket

Throttle position sensor

Detects extent of accelerator pedal depression using a potentiometer

Oil temperature sensor

Detects ATF temperature using a thermistor

Park/Neutral position switch

Detects selector lever position using contact switches

Stop lamp switch Detects brake operation/inoperation using contact switch on brake pedal

Vehicle speed sensor (2001 only)

Detects vehicle speed from speedometer gear

Sensor

Dual pressure switch Detects air conditioner operation/inoperation using dual pressure switch

A/T control relay Turns solenoid valve power supply circuit ON/OFF

DCC solenoid valve Regulates hydraulic pressure to damper clutch control valve

L/R solenoid valve Regulates hydraulic pressure to pressure control valve (for 1st gear or reverse shift control)

2nd solenoid valve Regulates hydraulic pressure to pressure control valve

UD solenoid valve Regulates hydraulic pressure to pressure control valve

OD solenoid valve Regulates hydraulic pressure to pressure control valve

Actuator

N-range lamp Indicates oil temperature warning, limp-in operation

101


INPUT SHAFT SPEED SENSOR/OUTPUT SHAFT SPEED SENSOR The input shaft speed sensor and output shaft speed sensor differ externally but are constructed in basically the same manner (fig. 54). The sensors utilize Giant Magnetoresistance (GMR) technology. The input shaft speed sensor detects the turbine speed at the UD clutch retainer. The output shaft speed sensor detects the transfer drive gear speed at the transfer driven gear.

1 Insert Electrode 3 Magnet 2 IC Chip (Built–In GMR Element) 4 Chip Parts

Figure 54 Input/Output Shaft Speed Sensor

102


Circuit Operation Note: Since both the input and output shaft speed sensors operate in the same

manner, only the input shaft speed sensor operation description is provided. The ignition switch supplies the input shaft speed sensor power and ground is provided by the PCM. The PCM provides 5 volts to the input shaft speed sensor. The input shaft speed sensor generates a square-wave pattern output (fig. 55). The sensor is opened and closed as the teeth on the underdrive clutch retainer pass the magnetic tip of the sensor. The GMR sensor is not affected by variations in teeth spacing or temperature changes resulting in a much more stable signal.

Figure 55 Input Shaft Speed Sensor Waveform

Vehicle Speed Signal The output shaft speed sensor provides a signal to the PCM that is directly proportional to vehicle speed. The PCM calculates a vehicle speed based on four pulses per one tire revolution and sends this signal to the speedometer. The output signal from the output shaft speed sensor is the same as the vehicle speed sensor that was discontinued at the beginning of the 2002 model year. The pinion factor setting is no longer required on this transmission.

103


ACTIVITY 5.1 INPUT SHAFT AND OUTPUT SHAFT SPEED SENSORS

1. At the classroom vehicle establish communication with the DRBIII® using the ST22 communication card (PCM/CIA Diagnostic Card [blue card] PN CH8425).

2. Raise the vehicle about one foot off the ground.

3. Disable the traction control (if equipped).

4. Start the engine and go to the Data List screen.

5. Shift the transmission through all of its gear ranges and record the following data (Use a calculator to determine gear ratios):

Gear Position 1st Gear 2nd Gear 3rd Gear 4th Gear Reverse

Crank A Sensor

Input Speed Sensor

Output Speed Sensor

Gear Ratio

Speed Sensor

6. Identify the signal wire for the input speed sensor

7. Turn the engine OFF and set up the DRBIII® as follows:

• Set up the DRBIII® to display a 5-volt square wave. • Press F2 to select the scope. • Connect the channel 1 lead to the input speed sensor signal wire. • Press F3 to view. • Adjust the time division to 2ms/division.

8. Start the engine.

9. Shift the transmission through all of its gear ranges and observe the lab scope display. What is the voltage range reading?

When finished, return all the equipment to its original condition.

104


Notes:

105


CRANKSHAFT POSITION (CKP) SENSOR The crankshaft position sensor monitors engine speed at the crankshaft sprocket. It is usually located behind the front crankshaft pulley. The crankshaft position sensor generates a pulse signal when the output circuit is opened and grounded. The sensor is opened and closed as the teeth on the crankshaft sprocket pass by. The sensor provides an input directly to the PCM to control shift quality, firm or sloppy, according to engine RPM. It is mainly used for torque converter engagement. The sensor compares the difference between engine RPM and input speed sensor RPM.

Circuit Operation The crankshaft position sensor power is supplied from the MFI relay, and the ground is provided on the vehicle body. The PCM provides 5 volts to the crankshaft position sensor output circuit (fig. 56).

1 From MFI Relay 3 PCM 2 Crankshaft Position Sensor 4 Camshaft Position Sensor

Figure 56 Crankshaft and Camshaft Position Sensor Circuit

106


ACTIVITY 5.2 CRANKSHAFT POSITION SENSOR

1. Identify the signal pin for the CKP

2. Identify the signal pin for the CMP

3. Set up the DRBIII® to display a 5-volt square wave.

4. Select “Scope” with the DRBIII®.

5. Connect the channel 1 lead to the CKP sensor signal.

6. Press F3 to view.

7. Adjust the time division to 40ms/division

8. Start the engine and observe the displayed pattern.

Record the voltage ranges

9. When finished, return all the equipment to its original condition.

107


THROTTLE POSITION SENSOR The throttle position (TPS) sensor is a 3-wire potentiometer operated by the throttle shaft and located on the throttle body. The input provides the PCM with throttle angle and rate of change information (how fast the throttle is opened or closed). The TPS input is also used by the PCM to reduce spark advance and change shift points depending on engine load (fig. 57). A failing or failed TPS may cause erratic shifting.

Figure 57 Throttle Position Sensor

Circuit Operation The TPS has three circuits arranged as follows:

A 5-volt reference signal is sent to pin 4 of the TPS from pin 81 of the PCM. Signal return comes from pin 3 of the TPS and goes to pin 84 of the PCM. TPS ground is at pin 1 of the TPS and goes to pin 92 of the PCM (fig. 58).

The 5-volt reference voltage enters the TPS, and goes through a resistor to ground. A wiper attached to the throttle shaft moves along this resistor and picks up the voltage that has been dropped by the resistor. This voltage is then interpreted by the PCM to determine throttle position.

Throttle Position Sensor Adjustment Whenever a TPS is replaced, it must be adjusted. Use the following procedure:

1. Connect the DRBIII® and establish vehicle communication or use a DMM between the TPS sensor output and ground circuits.

2. Turn the ignition switch to the “ON” position (but do not start the engine).

3. The throttle position sensor output voltage Standard Value is 535 – 735 mV.

4. If the output voltage is not within the standard value range, adjust by loosening the throttle position sensor mounting bolts and turning the throttle position sensor body.

108


1 PCM 4 Throttle Position Sensor 2 Sensor Ground 5 5V Supply 3 Sensor Signal

Figure 58 Throttle Position Sensor Circuit

109


ACTIVITY 5.3 THROTTLE POSITION SENSOR

1. Identify the signal pin for the TPS

2. Go to the classroom vehicle, connect the DRBIII® and establish communication.

3. Set the DRBIII® to the data list mode for item 11: TPS

4. Disconnect the TPS.

5. Record the voltage at the TPS connector pins and record your readings below:

TPS WIRE COLOR VOLTAGE READING

6. Reconnect the TPS.

7. Backprobe the TPS signal circuit.

8. With the throttle valve in the idle position, record the voltage

9. Is the TPS voltage within the standard value?

YES NO

10. Slowly open and close the throttle. Observe how the voltage makes a smooth transition.

11. With the throttle in the fully open position, record the voltage

12. Turn the ignition to the “LOCK” (OFF) position.

What are you looking for when monitoring the voltage on the TPS?

13. Is the sensor operating properly?

YES NO

110


Notes:

111


ATF TEMPERATURE SENSOR The A/T fluid temperature sensor is mounted to the valve body. The ATF temperature sensor and its connector are combined into a single unit and uses a Negative Temperature Coefficient (NTC) Thermistor. With an NTC thermistor, as heat increases, resistance decreases (fig. 59). High resistance in the sensor causes late shifts, low resistance causes early shifts.

If the ATF overheats (293°F or above) due to severe vehicle operating conditions, the N-range lamp flashes at a frequency of 2 Hz to warn the driver.

Circuit Operation The PCM applies 5 volts to the transmission fluid temperature sensor output. Ground is provided through the PCM. The transmission fluid temperature sensor is an NTC type of resistor. When the ATF temperature rises, the resistance decreases. The ATF temperature sensor output voltage rises when the resistance increases, and drops when the resistance decreases. High resistance can cause late shifts and low resistance can cause early shifts.

1 Thermistor 2 Connector

Figure 59 A/T Fluid Temperature Sensor

112


ATF TEMPERATURE CONTROL The PCM controls transmission operation based on ATF fluid temperature. In extremely hot or cold environments, the PCM can control each clutch and brake independently until the transmission reaches normal operating temperature. Refer to Table 7.

Note: Skip Shift or Jump Shift is defined as a transmission gear position that is shifted manually from N to N-2 or N+2 in both conventional operation and in Autostick mode.

Table 7 ATF Temperature Control Chart

Autostick ATF

Temperature

SHIFT Control

Adaptive Memory

Damper Clutch Control

Neutral Lamp Shift

UP Shift DOWN

Less than -29°C (-15.5°F)

2nd Gear is held

No No NO NO

-29°C (-15.5°F) to -7°C (19.5°F)

Standard Shift Pattern, No Skipped Shifts

No No No jump shift

No jump shift

-7°C (19.5°F) to 35°C (95°F)

Standard Shift Pattern

No No OK OK

35°C (95°F) to 40°C (113°F)

OK Standard Shift Pattern

Enabled No OK

40°C (113°F) to 125°C (257°F)


Enabled Yes (3rd & 4th)

OK OK

125°C (257°F) to 145°C (293°F) [or engine cooling temp greater than 110°C (242°F)]


Enabled Yes (2nd & 3rd & 4th)

OK OK

Greater than 145°C (293°F)


Enabled Yes (2nd & 3rd & 4th)

Blinking at 2Hz

OK OK

113


ACTIVITY 5.4 AUTOMATIC TRANSAXLE FLUID TEMPERATURE SENSOR

2.

1. Go to the classroom vehicle, connect the DRBIII and establish communication.

Read the transaxle fluid temperature with the engine OFF, key ON and record it below:

3. Start the engine. Using the DRBIII, set to data reading mode for item 15: A/T Fld Tmp Snsr. Is the sensor operating properly?

4.

Yes No

Refer to the service manual and identify which connector Pins must be probed to check the fluid temperature sensor circuit resistance:

5. Using the Ohmmeter setting on the DMM, measure the resistance of the fluid temp sensor circuit on the bench transmission and record your reading:

6. Compare the measured resistance with the chart below. Does your reading correspond with the data in the chart?

Yes No

TEMPERATURE RESISTANCE, K OHMS

At 0°C (32° F) 16.7 – 20.5

At 20° C (68° F) 7.3 – 8.9

3.4 – 4.2 At 40° C (104° F)

1.0 – 1.2 At 80° C (176° F)

At 100° C (212° F) 0.57 – 0.69

114


Park/Neutral Position Switch The Park/Neutral position switch detects the selector lever position using contact switches and is located on the transaxle housing. The Park/Neutral position switch is a 7-position type (fig. 60).

Circuit Operation Battery voltage is applied to the Park/Neutral position switch when the ignition switch is turned ON. Battery voltage is applied to the PCM when the selector lever is in the P range. The PCM interprets the selector is in the P range when this voltage is applied. As the selector lever is moved to the various positions (R, N, D, 3, 2, or L), the PCM interprets the position when battery voltage is applied to the corresponding circuits (108, 121, 102, 109, 122, or 110).

1 Junction Block 4 Powertrain Control Module 2 Park/Neutral Position Switch 5 Starting System 3 Backup light 6 Starting System

Figure 60 Park/Neutral Position Switch

115


ACTIVITY 5.5 TRANSAXLE RANGE SWITCH/PARK/

NEUTRAL POSITION SWITCH (INHIBIT SWITCH) CONTINUITY CHECK

1. At the classroom bench unit, use a DMM to make a continuity check at the terminals of the Transaxle Range Switch (fig. 61).

Figure 61 Transaxle Range Switch Continuity Check

2. Set the DMM to the Ohm Scale.

3. Move the selector lever to P, R, N, D, 3, 2, L, and Autostick positions.

4. Record resistance readings on the chart.

5. Is the switch operating properly?

Yes No

116


Selector Position Terminals Measured Resistance 3 – 8 P

9 – 10

R 7 – 8

4 – 8 N

9 – 10

D 1 – 8

3 5 – 8

2 2 – 8

1 6 - 8

117


TRANSAXLE CONTROL A cable controls the transaxle. The selector lever assembly has seven gear ranges: P, R, N, D, 3, 2, and L. A damper is fitted to the transaxle cable to minimize gear noise (fig. 62).

1 Transmission Control Cable 3 Damper 2 Selector Lever Assembly

Figure 62 Transaxle Control

118


ACTIVITY 5.6 PARK/NEUTRAL POSITION SWITCH AND CONTROL CABLE ADJUSTMENT

2. Loosen the control cable to manual control lever coupling nut to free the cable and lever (fig. 63).

4. Loosen the Park/Neutral position switch body mounting bolts and then turn the park/neutral position switch body so the hole in the end of the manual control lever and the hole in the flange of the park/neutral position switch body flange are aligned.

6. Gently pull the transaxle control cable in the direction of the arrow, and then tighten the adjusting nut.

8. Check that each range on the transaxle side operates and functions correctly for each position of the selector lever. Ensure the vehicle only starts in park and neutral.

1. Set the selector lever to the N position.

3. Set the manual control lever to the neutral position.

5. Tighten the Park/Neutral position switch body mounting bolts to the specified torque. Be careful at this time to not change the position of the switch body.

7. Check that the selector lever is in the N position.

Manual Control Lever

1 Adjusting Nut Transaxle Control Cable 3 2

Figure 63 Park/Neutral Switch and Control Cable Adjustment

119


A/C DUAL PRESSURE SWITCH The dual pressure switch detects air conditioner ON/OFF status. It is located in the high-pressure line.

Circuit Operation When the A/C is turned ON and the dual pressure switch is closed, the PCM (circuit 83) receives system voltage and determines the A/C compressor has been signaled to engage. When the A/C compressor is engaged, the PCM changes the shift points to compensate for the additional engine load. A failed dual pressure switch may cause delayed upshifts.

STOPLIGHT SWITCH The stoplight switch detects brake ON/OFF status using a contact switch on the brake pedal (fig. 64). The stop lamp switch is used to control EMCC operation in the transaxle.

1 Stoplight Switch 2 Brake Pedal Figure 64 Stoplight Switch

120


Circuit Operation Battery voltage is supplied to the stoplight switch. When the brake pedal is depressed, battery voltage is supplied to the PCM. The PCM determines the brake pedal is depressed and the stoplight switch is ON when battery voltage is sensed at the PCM (fig. 65).

1 Dedicated Fuse 4 To Stoplight 2 Stoplight Switch (Vehicles With

Cruise Control) 5 Powertrain Control Module (PCM)

3 To Cruise Control Module 6 Stoplight Switch (Vehicles Without Cruise Control)

Figure 65 Stoplight Switch Circuit Operation

121


AUTO-CRUISE CONTROL The auto-cruise control system allows driving without stepping on the accelerator pedal by setting a random speed between 40 km/h (25 mph) and 200 km/h (124 mph).

Circuit Operation The auto-cruise control – ECU shares inputs with the PCM such as throttle position, brake switch and the Park/Neutral position switch. The PCM provides the vehicle speed signal to the auto-cruise control – ECU over a dedicated circuit (fig. 66).

1 Powertrain Control Module - PCM 2 Auto-Cruise Control - ECU

Figure 66 Auto-Cruise Control

122


ACTIVITY 5.7 STOPLIGHT SWITCH CHECK

1. At the classroom vehicle, connect the DRBIII® and establish communication.

2. Turn the ignition switch to the ON position.

3. Set the DRBIII® to the data reading mode for item 26: Stoplight Switch.

4. When the brake pedal is depressed, the display should be ON.

5. When the brake pedal is released, the display should be OFF.

6. Turn the ignition switch to the LOCK (OFF) position.

7. Is the switch operating properly?

YES NO

123


SOLENOID VALVES The solenoid valves are located in the valve body (fig. 67). The DCC, L/R, 2nd, UD, and OD solenoid valves regulate hydraulic pressure to the respective pressure control valves to control gear shifts.

1 Underdrive Solenoid Valve 4 Low/Reverse Solenoid Valve 2 2nd Solenoid Valve 5 Overdrive Solenoid Valve 3 Torque Converter (Damper) Clutch

Solenoid Figure 67 Solenoid Valve Location

124


The solenoid valves are a normally open type which allow the passage of hydraulic fluid between the supply and output ports when no electrical current is flowing (fig.68). The solenoid valves are duty-cycled by the PCM from 0% to 100%. The friction elements are fully applied when the solenoid is at 0% and fully released when the solenoid valve is at 100% (refer to Table 8).

1 Plunger 3 Supply Port 2 Output Port 4 Exhaust Port

Figure 68 Solenoid Valve

Table 8 Solenoid Valve Operation

Solenoid Valves Gear

L/R 2ND UD OD DCC (Ref.) 1st OFF ON OFF ON OFF

2nd ON OFF OFF ON ON

3rd ON ON OFF OFF ON

4th ON OFF ON OFF ON

Reverse OFF ON ON ON OFF

N-P OFF ON ON ON OFF

125


Circuit Operation The A/T control relay supplies system voltage to each solenoid valve. Each solenoid valve closes when energized (ON), and opens when de-energized (OFF). The PCM energizes or de-energizes each solenoid valve based on input data from sensors such as throttle position sensor, park/neutral position switch, stoplight switch, vehicle speed sensor, input shaft speed sensor, output shaft speed sensor, and the A/T fluid temperature sensor. The PCM provides the ground to energize each solenoid. The ground time is displayed as a percent on the scan tool. As each solenoid is energized or de-energized, it influences hydraulic pressure in the transmission applying and releasing elements (fig. 69).

1 A/T Control Relay 4 Overdrive Solenoid Valve 2 Underdrive Solenoid Valve 5 Low/Reverse Solenoid Valve 3 2nd Solenoid Valve 6 Powertrain Control Module (PCM)

Figure 69 Solenoid Valve Circuit Operation

126


ACTIVITY 5.8 SOLENOID VALVE CHECK

TASK ONE – ACTUATOR TEST 1. At the classroom vehicle, connect the DRBIII® and establish communication using

the ST22 Communication Card.

2. Select ELC-4AT.

3. Select Actuator Tests.

4. Actuate each solenoid. What is the audible frequency of each solenoid? Circle the correct answer in the chart below:

ACTUATOR TEST SOLENOID FREQUENCY SPEED

LR Sol Fast Slow

UD Sol. Fast Slow

2ND Sol. Fast Slow

OD Sol. Fast Slow

DCC Sol. Fast Slow

5. Actuate each indicator. What is displayed on the instrument cluster? Circle the correct answer in the chart below:

INDICATOR TEST

1ST SHIFT LAMP P R N D 4 3 2 1

P R N D 4 3 2 1

3RD SHIFT LAMP P R N D 4 3 2 1

4TH SHIFT LAMP P R N D 4 3 2 1

LAMP INDICATION

2ND SHIFT LAMP

127


TASK TWO – VIEW DATA LIST

4.

1. Raise the vehicle approx. one foot off the ground.

2. Disable the Traction Control (if equipped).

3. Start the engine and go to the Data List screen on the DRBIII®.

Shift the transmission through all of its gear ranges and, using the chart below, fill in the valve status for each gear position.

NOTE: (100% solenoid duty=Solenoid ON, 0% solenoid duty=Solenoid OFF)

SOLENOID VALVE STATUS CHART SOLENOID VALVE

GEAR POSITION LR 2ND UD OD 1ST

2ND

3RD

4TH

REVERSE

N-P

128


AUTOMATIC TRANSAXLE (A/T) CONTROL RELAY The A/T control relay provides the power supply for the solenoid valves (figs. 70 and 71). In the event of an A/T relay failure, the transaxle goes into major limp-in mode, resulting in 3rd and reverse gear operation only.

1 Battery 2 A/T Control Relay

Figure 70 2001 A/T Control Relay

1 Battery 2 A/T Control Relay

Figure 71 2002 A/T Control Relay

129


Circuit Operation A/T control relay receives battery positive voltage from the battery. When turning the ignition switch to ON, the PCM receives battery positive voltage from the ignition switch (not shown in the diagram). The PCM applies a voltage to the A/T control relay, and the A/T control relay is turned ON.

When the A/T control relay switch is turned ON, the battery supplies system voltage to the PCM. If voltage is not present the PCM sets an A/T relay code (fig. 72).

1 Fusible Link 6 Connector Pin 89 2 Junction Block 7 Sense Circuit 3 A/T Control Relay 8 Powertrain Control Module (PCM) 4 To the Solenoid Valves 9 Connector Pin 50 5 Connector Pin 77

Figure 72 A/T Control Relay Circuit Operation

130


ACTIVITY 5.9 A/T CONTROL RELAY CHECK

1. Go to the classroom vehicle, connect the DRBIII® and establish communication with the automatic transaxle using the ST22 Communication Card.

2. Set the DRBIII® to the Data List mode for item 54: ELC Relay Volt.

3. The voltage should be battery positive.

4. Turn the ignition switch to the “LOCK” (OFF) position.

5. Is the relay operating properly?

YES NO

131


AUTOSTICK SELECT SWITCH The select switch allows the driver to change between manual and automatic gear selections. The shift switch sends a signal to the PCM to either upshift or downshift (fig. 73). The transaxle cannot take off in 3rd gear despite efforts to force an upshift during normal Autostick mode. In addition, there is no reverse-to-drive lockout. There is drive-to-reverse lockout. There is no lockout in limp-in mode.

1 Upshift 4 Select and Shift Switches 2 Downshift 5 Shift Cable 3 Manual Gate 6 Main Gate

Figure 73 Select Switch and Shift Switch

132


Circuit Operation If the select switch is set to manual mode, battery positive voltage is applied to the PCM. When the shift switch is moved to the UP position, battery positive voltage is supplied to the PCM. When the shift switch is moved to the DOWN position, battery positive voltage is applied to the PCM (fig. 74).

1 Ignition Switch 7 Shift Switch Assembly 2 Park/Neutral Position Switch 8 Select Switch 3 Up 9 Shift Switch 4 Down 10 To Combination Meter 5 Autostick 11 Powertrain Control Module (PCM) 6 Auto Mode

Figure 74 Select Switch and Shift Switch Circuit Operation

133


ACTIVITY 5.10 AUTOSTICK SELECT SWITCH

1. At the classroom vehicle, connect the DRBIII® and establish communication.

2. Look at the Data List monitor operation.

3. Observe the Select Switch status.

4. To confirm proper operation, place the shift lever in Autostick mode.

5. Verify which switch state is displayed on the DRBIII®.

6. Toggle the shifter between upshift and downshift and record the DRBIII® switch status in the chart below:

DRBIII® SWITCH STATUS CHART SWITCH POSITION UPSHIFT DOWNSHIFT

Select Switch

Up (+) Switch

Down (-) Switch

134


CONTROL OVERVIEW Shift Control With the new Autostick automatic transaxle, a dedicated solenoid valve carries out the hydraulic control of each clutch and brake. Each solenoid valve is controlled independently, enabling a system of direct clutch-to-clutch control during gear shifts. This next-generation system provides highly precise control of clutch operation and significant improvements in gear shift feeling and response.

Shift Pattern Control The shift pattern is optimized by the Autostick in accordance with road conditions and the manner in which the driver operates the vehicle.

Select Switch and Shift Switch The select and shift switches are built into the shift switch assembly. The select switch determines Manual Mode or Auto Mode as commanded by the driver. In Manual Mode, the shift switch provides either an upshift or downshift command to the PCM.

135


AUTOSTICK Autostick is a driver-interactive transaxle feature that offers manual gear shifting capability. When the shifter is moved into the Autostick position, the transaxle remains in whatever gear it was using before Autostick was activated. Once in the manual gate, the shifter can be “bumped” forward for an upshift or rearward for a downshift. The instrument cluster illuminates the selected gear. The vehicle can be launched in 1st or 2nd gear while in the Autostick mode (figs. 75 and 76). Speed control is deactivated once the transaxle is shifted into 2nd gear. Shifting into OD position cancels the Autostick mode, and the transaxle resumes the OD shift schedule.

1 Throttle Opening (%) 4 Output Shaft Speed (r/min) 2 2-3 Movement Range 5 Vehicle Speed (mph) 3 3-4 Movement Range 6 Thick Line: Standard Shift Pattern

Figure 75 Upshift Pattern

136


1 Low 5 3-4 Movement Range 2 Low, 2nd 6 Output Shaft Speed (r/min) 3 Low, 2nd, 3rd 7 Vehicle Speed (mph) 4 2-3 Movement Range

Figure 76 Downshift Pattern

137


ADAPTIVE MEMORY Adaptive memory allows the Autostick system to learn and respond to different driving habits and conditions. Adaptive memory monitors inputs from the TPS, VSS, and stop lamp switch. If the driver pushes the brake pedal frequently on a downhill road, the computer causes downshifts to occur relatively early to provide engine braking. If the driver often presses the accelerator pedal, the computer tends to prevent downshifts, which suppresses engine braking (fig. 77).

1 Driver Who Often Uses Brake Pedal 2 Driver Who Often Presses Accelerator Pedal

Figure 77 Effects of Learning on Downhill Road

138


Hydraulic Control During Gear Shifts Clutch-to-Clutch Control During gear shifts, the new A/T provides simultaneous control of clutches and brakes that are to be engaged and disengaged. As torque applied to the clutches and brakes that are to be engaged increases, there is a proportional reduction in pressure to those that are to be disengaged.

Precise control of pressure during both engagement and disengagement ensures control is optimally timed and matched to the capacities of the brakes and clutches. This prevents interlocking and sudden revving of the engine, and provides smoother, more responsive gear shifts (fig. 78).

1 Upward Shift 4 Disengaging Clutch 2 Downward Shift 5 Time 3 Engaging Clutch 6 Fluid Pressure

Figure 78 Clutch to Clutch Control

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Feedback Control and Learning Control To assure the driveshaft torque changes optimally during and throughout every gearshift, a feedback control function makes changes in the transaxle input shaft speed consistent with a pre-established pattern (fig. 79). This allows for increased stability in the gearshift feeling.

Functional Learning Based on conditions during previous operations, the feedback control function makes any necessary corrections to the fluid pressure at the beginning of each gearshift to compensate for changes in engine performance and transaxle behavior over time.

Driver Learning Adaptive memory determines solenoid operation to control shift timing. Driver operation and clutch wear are used to modify adaptive memory. Fill rate for clutch timing engagement is based on input shaft speed sensor and output shaft speed sensor signals alone. If it varies, the transaxle tries to compensate and achieve the correct ratio four times before placing the transaxle into limp-in. During normal operation the transaxle determines this adaptive memory by looking at the gear ratio. This is accomplished by multiplying output shaft speed times a gear ratio to ensure it matches the correct input shaft speed.

Notes:

140


1 Upward Shift 4 Turbine Speed 2 Downward Shift 5 Target 3 Turbine Speed 6 Time

Figure 79 Feedback/Learning Control

141


Damper Clutch Control Damper clutch engagement is used to improve fuel economy and lower transaxle temperature. With the damper clutch applied, the torque converter is no longer slipping, resulting in lower engine RPM and less tail pipe emissions. Also, with the damper clutch applied, the torque converter is no longer multiplying torque. Because of this reduced workload, transmission fluid temperature decreases. The damper clutch control (DCC) solenoid is a normally open solenoid that applies release pressure.

The damper clutch control (DCC) solenoid is applied under the following conditions (figs. 80, 81 and 82):

• Accelerator off idle (1700-1800 rpm) • A/T fluid above a certain temperature (113°F.) • Steady throttle • Gear position status (3, 4, or D) • No brake switch input

1 Throttle Position Voltage 5 Deceleration Lock-Up Zone 2 Disengaged 6 Output Shaft Speed R/Min 3 Lock-Up 7 Partial Lock-Up Zone 4 Lock-Up Zone 8 Throttle Opening Percentage

Figure 80 Damper Clutch Control (3rd, 4th and D)

142


1 Throttle Position Voltage 5 Output Shaft Speed R/Min 2 Disengaged 6 Partial Lock-Up Zone 3 Lock-Up 7 Throttle Opening Percentage 4 Lock-Up Zone

Figure 81 Damper Clutch Control (3rd Gear)

1 Throttle Position Voltage 5 Output Shaft Speed R/Min 2 Disengaged 6 Partial Lock-Up Zone 3 Lock-Up 7 Throttle Opening Percentage 4 Lock-Up Zone

Figure 82 Damper Clutch Control (4th Gear)

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LIMP-IN (FAIL-SAFE) FUNCTION AND DIAGNOSIS In the event of a fault in the PCM or any of the sensors and actuators, or in the event of seriously erroneous operation on the part of the driver, a limp-in function controls the transaxle. If the PCM detects out-of-parameter conditions in monitored circuits, it has the capability to request limp-in or fail-safe operation (fig. 83).

LIMP-IN (FAIL-SAFE) OPERATION (CONTROL RELAY OFF) In the event of an electronic or mechanical control system fault (limp-in), a switch valve and fail-safe valve arrangement enables operation in 3rd gear or reverse.

When the control relay is OFF and the limp-in mechanism operates, the supply of hydraulic pressure from the L/R pressure control valve to the L/R brake is released by the switch valve. Fail-safe valve A releases the L/R brake hydraulic pressure. When the solenoid valve is turned OFF, hydraulic pressure to the 2nd brake is released. Also, the hydraulic pressure from the 2nd pressure control valve is released by fail-safe valve B.

Notes:

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1 Fail-Safe Valve A 13 OD Solenoid Valve 2 UD Clutch 14 Manual Valve 3 Accumulator 15 Regulator Valve 4 OD Clutch 16 Relief Valve 5 Fail-Safe Valve B 17 Oil Pump

Switch Valve 18 Oil Pan 7 L/R Solenoid Valve 19 Oil Filter 8 2nd Pressure Control Valve 20 Torque Converter Pressure Control




One-Way Check Ball

Restrictor

Fluid Exhaust

Pressure Tap

6

Figure 83 Fail-Safe Operation

145


FAIL-SAFE VALVE A OPERATION When the vehicle is traveling forward, fail-safe valve A prevents hydraulic pressure from going to the L/R brake in the event of a limp-in condition. In reverse, fail-safe valve A changes the fluid passage back to the L/R brake.

FAIL-SAFE VALVE B OPERATION In the event of a limp-in condition (when the control relay is OFF), fail-safe valve B interrupts the supply of hydraulic pressure from the 2nd pressure control valve to the 2nd brake.

MAJOR LIMP-IN All solenoid valves are off; only 3rd gear and reverse are available.

MINOR LIMP-IN All solenoid valves are off; only 2nd (manual), 3rd and reverse are available.

Diagnostic Codes Among the diagnostic codes, higher values represent limp-in items.

• Diagnostic items: Code Nos. 11-15, 21, 25, 51, 52, 56 • Limp-in items: Code Nos. 22, 23, 31-36, 41-46, 54, 55, 71

Indication Method and Sequence:

• During normal vehicle operation, if the limp-in function becomes enabled, the N-range lamp flashes at a frequency of 1 Hz to inform the driver. This occurs only in the D-range.

• When no diagnostic codes are held in memory, (i.e. under normal conditions), the N-range lamp flashes at 2 Hz, caused by transmission overheat.

• Conditions considered out of parameter but not critical, and unable to cause internal transaxle damage, are logged as a fault. A substitute value is used and a safe but limited operation is adopted.

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Display Sequence Diagnostic codes are indicated in the order in which they were issued, with limp-in items followed by diagnosis items. This sequence is then repeated.

Memorization • Up to eight diagnosis items and three limp-in items can be memorized. • If the memory capacity is exceeded, diagnosis and limp-in items in the

memory are overwritten, starting with the oldest. • No code can be memorized more than once.

Diagnostic Code Deletion • Automatic Deletion: All diagnosis codes are deleted from memory the 200th

time the ATF temperature reaches 50°C/122°F after memorization of the most recent diagnosis code.

• Forced Deletion: Memorized diagnosis codes can be deleted using the DRBIII® provided the engine is OFF, the ignition switch is ON, the vehicle is not moving, and the transaxle is not in limp-in.

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DATA LIST A/T PCM input and output data is communicated to the DLC. The data can be read by connecting a DRBIII® unit to the DLC. Refer to Table 9 for the data list.

Table 9 Data List

Data List No. Item Unit

11 TPS (Throttle position sensor) mV

15 A/T Fld Tmp Snsr °F

21 Crank A. Sensor (Crankshaft Position Sensor) RPM

22 Input Speed Snsr RPM

23 Output Speed Snsr RPM

26 Stop Lamp Switch ON/OFF

29 Speed Sensor MPH

31 L/R Solenoid Duty %

32 U/D Solenoid Duty %

33 2nd Solenoid Duty %

34 O/D Solenoid Duty %

36 D/C Solenoid Duty %

52 D/C RPM Slip RPM

54 EEC Relay Volt V

57 Engine Load %

61 Inhibitor Switch PARK, REVERSE, NEUTRAL, DRIVE

63 Shift Position PARK/NEUT, REVERSE, 1ST GEAR, 2ND GEAR, 3RD

GEAR, 4TH GEAR

65 A/C Relay ON/OFF

66 OD Off Signal ON/OFF

67 Select Switch (vehicles with Autostick) ON/OFF

68 Up (+) Switch (vehicles with Autostick) ON/OFF

69 Down (-) Switch (vehicles with Autostick)

ON/OFF

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ACTUATOR TEST By sending signals from the DRBIII® to the PCM, it is possible to force-operate the actuators for test purposes. Refer to Table 10 for actuator test information

Table 10 Actuator Test

Item No.

Target Actuator Test Test Conditions

1 L/R solenoid valve

2 UD solenoid valve

3 2nd solenoid valve

4 OD solenoid valve

6 DCC solenoid valve

Solenoid valve selected by DRBIII® operated at 50% duty ratio for 5 seconds; all other solenoid valves de-energized

12 A/T control (ELC) relay

A/T control (ELC) relay turned OFF for 3 seconds

(1) Ignition switch = ON;

(2) Selector lever = P range;

(3) Engine speed = 0 r/min;

(4) Vehicle speed = 0 km/h;

(5) Throttle (accelerator) opening voltage (1 V);

(6) Idle position switch = ON

AUTOSTICK STOP COMMAND (MPI) By sending a signal from the DRBIII® to the PCM, it is possible to stop Autostick operation. (If Autostick operation is stopped, this condition continues until the ignition is turned OFF). Refer to Table 11.

Table 11 Autostick Stop Command

Item No.

Item Details

14 Autostick Autostick control stopped; gear shifts executed in accordance with standard shift pattern

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MODULE 6 DIAGNOSIS

Note: For current diagnostic flow chart information refer to the Service Manual.

N-RANGE LAMP If a fault occurs with any of the components shown in Table 12, the N-range lamp flashes to notify the driver of a fault (fig. 84). The N-range lamp flashes at a frequency of approximately 2 Hz if the transmission temperature is too high and 1 Hz for a fault related to the components in the table below. Use the DRBIII® or the N-range lamp to take a reading of the diagnosis codes.

Table 12 N-range Lamp Flashing Items

A/T control relay



Each solenoid valve

Out of phase at each shift point (gear ratio error)

Caution: If the N-range lamp is flashing at a frequency of approximately 2 Hz (faster than at 1 Hz), it means the automatic transmission fluid temperature is too high. Stop the vehicle in a safe place and wait until the N-range lamp switches off.

Method of Reading the Diagnosis Code

Figure 84 N-Range Lamp

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ACTIVITY 6.1 N-RANGE LAMP FUNCTIONS

1. Turn the ignition switch to the ON position.

2. Move the gearshift lever to the D position.

3.

4.

Remove the A/T Control (ELC) Relay.

Does the N-range lamp flash?

How fast? Is this a problem?

Why or Why not?

5. Turn the ignition switch to the “LOCK” (OFF) position.

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ACTIVITY 6.2 TORQUE CONVERTER STALL TEST

This test measures the maximum engine speed when the selector lever is at the D or R position. The torque converter stalls when testing the operation of the torque converter and one-way clutch operation. The holding performance of the clutches and brakes in the transmission can be checked simultaneously to help reduce the amount of time the transmission fluid and components are heated unnecessarily.

Caution: Do not let anyone stand in front of or behind the vehicle while this test is being carried out.

1. Check the ATF level and temperature and the engine coolant temperature.

• Fluid level: At the HOT mark on the oil level gauge • Fluid temperature: 80-100°C (176-212ºF) • Engine coolant temperature: 80-100°C (176-212ºF)

2. Use the DRBIII® set up for the tachometer.

3. Chock both rear wheels.

4. Fully apply the parking brake.

5. Start the engine.

6.

7.

Firmly apply the service brakes.

Move the selector lever to the D position. Fully depress the accelerator pedal and record the maximum engine speed:

Caution: The throttle should not be held fully open for more than eight seconds. If repeating the stall test, move the selector lever to the N position and run the engine at 1,000 r/min to let the automatic transmission fluid cool down before performing subsequent tests.

8. Move the selector lever to the R position. Fully depress the accelerator pedal and record the maximum engine speed:

Standard value stall speed: 2,100-2,600 r/min

9. Is the torque converter operating properly?

YES NO

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ACTIVITY 6.2 (CONTINUED) TORQUE CONVERTER STALL TEST

• Underdrive clutch slippage

TORQUE CONVERTER STALL TEST RESULTS 1. Stall speed is too high in both D and R ranges.

Possible Causes:

• Low line pressure

2. Stall speed is too high in D range only.

Possible Cause:

3. Stall speed is too high in R range only.

Possible Cause:

• Reverse clutch slippage • Low and reverse brake slippage

4. Stall speed too low in both D and R ranges.

Possible Causes:

• Malfunction of torque converter • Insufficient engine output

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ACTIVITY 6.3 CLUTCH TESTS

For this activity you will use the DRBIII® on the classroom vehicle to monitor engine rpm.

1. What gear position should the transaxle be placed in to confirm whether the L/R is functioning correctly?

2. Why is the transaxle placed in reverse gear to test the L/R brake?

Can the 2nd brake operation be verified with a clutch test on a Non-Autostick vehicle?

3.

4. What gear position should the transaxle be placed in to test the UD clutch?

Caution: Use the DRBIII® to monitor the engine rpm and applied clutch for a limited time to prevent transaxle damage.

154


ACTIVITY 6.4 HYDRAULIC PRESSURE TEST

1. Warm up the engine until the automatic transmission fluid temperature is 80-100°C.

2. Raise and support the vehicle so the wheels are free to turn.

3. Connect the special tools (2,942-kPa oil pressure gauge [MD998330], joints [MD998332, MD998900] and seven blue transducers (0-2068.4 kPa/0-300 psi) to each pressure discharge port.

4. Measure the hydraulic pressure at each port under the conditions given in the standard hydraulic pressure table, and check that the measured values are within the standard value ranges.

5. If a value is outside the standard range, correct the problem while referring to the hydraulic pressure test diagnosis table.

Note: • • • • •

2nd: Second brake pressure port UD: Underdrive pressure port L/R: Low/reverse brake pressure port DA: Torque converter apply pressure port DR: Torque converter release pressure port

• RV: Reverse clutch pressure port • OD: Overdrive clutch pressure port

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ACTIVITY 6.5 STANDARD HYDRAULIC PRESSURE TEST

For this activity you will use the classroom vehicle, special tool oil pressure gauge (MD998330), adapters (MD998332, MD998900), seven blue transducers (0-2068.4 kPa/0-300 psi) and the chart below. Record your findings on the chart and compare them to the Service Manual specifications.

MEASUREMENT CONDITION

STANDARD HYDRAULIC PRESSURE kPa (psi)

Selector Lever Position

Shift Position

Engine Speed (rpm)

Under-Drive Clutch (UD)

Reverse Clutch (RV)

Over-Drive Clutch (OD)

Low/ Reverse Brake (LR)

Second Brake (2ND)

Torque Converter (DR)

P

- 2,500

R

Reverse 2,500

N

- 2,500

L (vehicles without Autostick) or Autostick (Vehicles with Auto-stick)

1st gear 2,500

2 (Vehicles without Autostick) or Autostick (Vehicles with Auto-stick)

2nd gear 2,500

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ACTIVITY 6.5 (CONTINUED) STANDARD HYDRAULIC PRESSURE TEST

MEASUREMENT CONDITION

STANDARD HYDRAULIC PRESSURE kPa (psi)

Selector Lever Position

Shift Position

Engine Speed (rpm)

Under-Drive Clutch (UD)

Reverse Clutch (RV)

Over-Drive Clutch (OD)

Low/ Reverse Brake (LR)

Second Brake (2ND)

Torque Converter (DR)

3 (Vehicles without Autostick) or Autostick (Vehicles with Auto-stick)

3rd gear 2,500

D (Vehicles without Autostick) or Autostick (Vehicles with Auto-stick)

4th gear 2,500

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SPECIAL TOOLS TOOL TOOL NUMBER AND

NAME APPLICATION

MD998333-01 or MD998333 Oil pump remover

Removal of oil pump.

MD998333 or MD998333-01 Oil pump remover

Removal of oil pump.

8622 or MD998924 Spring compressor retainer

Use with spring compressor.

MD998924 or 8622 Spring compressor retainer

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SPECIAL TOOLS (CONTINUED)

TOOL TOOL NUMBER AND NAME

APPLICATION

MD991625-01 Socket (41 mm)

Removal and installation of transfer drive gear jam nut (F4A42).

C-3575-A Spring compressor

Removal and installation of one-way clutch inner race snap ring (F4A42).

MD998338 or MD5059A Spring compressor

MD5059A or MD998338 Spring compressor

Removal and installation of one-way clutch inner race snap ring (F4A51).

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APPLICATION

MD990607-01 Torque wrench socket

Removal and installation of output shaft nut.

MD998412 Guide Installation of oil pump and transfer drive gear.

MB991631 Clearance dummy plate

Measurement of reaction plate low/reverse brake and second brake end plays (F4A42).

MB991632 Clearance dummy plate

Measurement of reaction plate low/reverse brake and second brake end plays (F4A51).

MD998913 Dial gauge extension

Measurement of low/reverse brake endplay. Use with C-3339 dial indicator.

160




APPLICATION

C-4171 Handle or MB990938

P-334 Bearing remover

Removal of each bearing output shaft taper roller bearing (differential ball bearing).

8594 Installer adapter

Installation of output shaft taper roller bearing outer race.

C-3717 Bearing installer

Installation of output shaft taper roller bearing outer race.

• Installation/removal of input shaft rear bearing.

• Use with 8590 for installation. • Use with 8591 for removal.

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APPLICATION

MB998717 Installer adapter

Installation of cap.

D-146 Installer adapter Installation of differential taper

roller bearing outer race (F4A42). Use with C-4171.

MD998907 Spring compressor

Removal and installation of overdrive clutch snap ring. Use with 8622.

MB991790 Spring compressor

Measurement of reverse clutch end play (F4A42). Use with 8622.

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APPLICATION

8621 Spring compressor

Measurement of reverse clutch end play (F4A51). Use with 8622.

8595 Bearing remover

Removal of output shaft taper roller bearing and transfer driven gear.

MD998805 Installer adapter (48)

Installation of output shaft taper roller bearing (F4A42) and transfer driven gear (F4A42).

8592 Installer adapter (F4A51)

8597 Installer adapter (F4A42)

Installation of output shaft taper roller bearing. Use with C-4171.

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APPLICATION

C-4965 Installer adapter (42)

Installation of differential taper roller bearing.

C-3095 Installer adapter (50)

Installation of transfer driven gear (F4A51), differential taper roller bearing (F4A51).

6906 Flushing tool Flushing cooler and tube.

MD998334 Oil seal installer

Installation of oil pump oil seal.

164




APPLICATION

MD998907 Spring compressor

Removal and installation of underdrive clutch snap ring. Use with 8622.


Measurement of underdrive clutch and overdrive clutch end plays (F4A42). Use with 8622.


Measurement of underdrive clutch and overdrive clutch end plays (F4A51). Use with 8622.

MD998325 Oil seal installer

Installation of drive shaft oil seal.

5058A-3 Screw Use with MD5059A spring compressor.

165


GLOSSARY DIAGNOSTIC TROUBLE CODE (DTC): A DTC is a two-digit number (P-code) stored in the powertrain control module memory, indicating a malfunction with the transaxle or its control system. Obtained by using the DRBIII® scan tool. The DRBIII® retrieves and displays the code(s).

DUTY CYCLE: Duty cycle is comprised of the time when the solenoid valves are energized, preventing oil flow to the clutches and brakes.

HERTZ: The frequency of an event (cycles per second).

LAND: Flat surface(s) on a valve which cause the valve to be moved to the left or right when the fluid pressure pushing against the land is high enough to overcome spring pressure, causing an upshift or downshift.

LIMP-IN (MAJOR): A condition where the powertrain control module shuts off the internal controls of the transaxle to prevent or reduce the chance of internal transaxle damage. Only 3rd gear and reverse available.

LIMP-IN (MINOR): 2nd (manual), 3rd gear and reverse available.

LOW/REVERSE BRAKE: The low/reverse brake operates in 1st and reverse gears when the vehicle is parked and during manual operation. The low/reverse brake is located between the reverse clutch and the output planetary carrier.

OIL PUMP: The oil pump is a hydraulic pump used to circulate fluid under pressure to apply clutches, lubricate components and cool the transmission.

OVERDRIVE: Overdrive is a gear range in the transaxle with an output speed greater than its input speed. For example, every 0.75 revolutions of input, the output rotates 1 revolution (0.75:1).

OVERDRIVE CLUTCH: Located in the reverse/overdrive clutch assembly, the overdrive clutch is used in 3rd gear, 3rd gear limp-in and 4th gear.

OVERRUNNING CLUTCH: The overrunning clutch is a holding clutch located in the planetary gear set. It is used in D-first, 2-first and 3-first.

PORT: The port is an opening in a valve through which fluid flow is controlled to the various clutches and brakes when the port opens or closes.

REACTION PLATE: The reaction plate is a component within a clutch assembly that backs up or retains the pressure exerted on the clutch pack from the hydraulic pressure force of the piston when applied.

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GLOSSARY (CONTINUED)

RETURN SPRING: The return spring is located in the reverse/overdrive clutch, and is used to help release the overdrive clutch piston.

REVERSE CLUTCH: The reverse clutch is located in the reverse/overdrive clutch and is used in reverse only.

SECOND BRAKE: The second brake operates in 2top of the low/reverse brake

VALVE BODY: The valve body is a component of an automatic transaxle that contains the hydraulic valves. The valves are shifted to apply friction elements that control planetary gearset components.

nd and 4th gears and is located on

SOLENOID: The solenoid is an electrical component comprised of a series winding, hollow iron core and a movable spring-loaded plunger or rod. When energized or turned on, it creates a magnetic field that moves the plunger against spring pressure. It converts electrical energy into mechanical force and movement and is used in the transaxle to open or close a valve.

SWITCH VALVE: The switch valve prevents the application of the low/reverse brake when the solenoid is OFF during limp-in operation. It is also used to reduce hydraulic line pressure in 3rd and 4th gears.

TRANSAXLE RANGE SENSOR: The transaxle range sensor is a component that allows for accurate transmission gear position measurement.

UNDERDRIVE CLUTCH: Located on the input shaft, the underdrive clutch is used in all gear ranges except park, reverse, neutral and 4th.

VENT: The vent consists of holes in the clutch packs that allow fluid to be released when the solenoid to the clutch is duty cycled.

WAVE SPRING: Located in the low/reverse brake, the wave spring is used to cushion the application of the low/reverse brake.

167


Notes:

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