chapter 24 heavy-duty truck axle service and repair

Click here to load reader

Post on 16-Dec-2015

245 views

Category:

Documents

5 download

Embed Size (px)

TRANSCRIPT

  • Slide 1
  • Chapter 24 Heavy-Duty Truck Axle Service and Repair
  • Slide 2
  • Objectives (1 of 2) Describe the lubrication requirements of truck and trailer dead axles. Outline the lubrication service procedures required for truck drive axle assemblies. Perform some basic level troubleshooting on differential carrier gearing. Outline the procedure required to disassemble a differential carrier.
  • Slide 3
  • Objectives (2 of 2) Disassemble a power divider unit. Perform failure analysis on power divider and differential carrier components. Reassemble power divider and differential carrier assemblies.
  • Slide 4
  • Axle Fill and Drain Plugs
  • Slide 5
  • Axle Lube Viscosity See Table 24-1 on page 706 in the textbook.
  • Slide 6
  • Shop Talk Draining lubricants when warm ensures that contaminants are still suspended and also reduces drain time.
  • Slide 7
  • Power Divider Oil Fill and Drain Plugs
  • Slide 8
  • Checking the Lube Level
  • Slide 9
  • Proper Lubricant Levels
  • Slide 10
  • Caution On most drive axles, there is no external visual means of checking lubricant level in the wheel end, so the importance of making sure the drive axle lubricant level is correct cannot be overemphasized. Raising each side of an axle with a jack ensures oil fills the wheel-end hub cavity. Make a final check of the differential carrier oil level after tilting the axle from both sides.
  • Slide 11
  • Wheel Hub Lube Cavity
  • Slide 12
  • Differential Carrier Identification
  • Slide 13
  • Axle Identification
  • Slide 14
  • Crown Gear and Pinion Identification
  • Slide 15
  • Failure Analysis Shock load Fatigue Spinout Faulty lubrication Normal wear
  • Slide 16
  • Caution Most driver-abuse generated failures do not cause an instantaneous equipment failure. The equipment failure can take place some time after the driving incident that generated it. This is important to remember when attempting to attribute blame in fleets that do not assign drivers dedicated trucks.
  • Slide 17
  • Fracture Patterns
  • Slide 18
  • Surface Failure Patterns
  • Slide 19
  • Torsional Failure
  • Slide 20
  • Bending Failure Patterns
  • Slide 21
  • Spinout
  • Slide 22
  • Always Support the Truck With Axle Stands
  • Slide 23
  • Shop Talk You sometimes have to use more force to pop axle shafts than can be delivered using a drift and 4-lb. hammer. When this method does not work, use a 16- lb. sledgehammer directly on center of the axle shaft flange; use a swing of the sledgehammer, letting the weight of the hammer do all of the work.
  • Slide 24
  • Caution Most of the weight of a differential carrier assembly is on the inboard side of its mounting flange. Ensure that the assembly is properly fastened to the jacking device and that your body is never positioned under the carrier.
  • Slide 25
  • Thrust Screw
  • Slide 26
  • Marking the Carrier Components
  • Slide 27
  • Lock Plate and Adjusting Rings
  • Slide 28
  • Removing the Bearing Cap and Adjusting Ring
  • Slide 29
  • Differential Spider Gears
  • Slide 30
  • Drill and Punch Out Rivets
  • Slide 31
  • Caution Do not remove the rivet heads or rivets with a chisel and hammer because this can damage the flange case half or enlarge the rivet holes, resulting in loose rivets.
  • Slide 32
  • Remove the Ring Gear
  • Slide 33
  • Removing the Pinion Flange or Yoke
  • Slide 34
  • Bearing Cage Removal
  • Slide 35
  • Removing Pinion with Bearing Cage
  • Slide 36
  • Pressing the Drive Pinion from the Bearing Cage
  • Slide 37
  • Pinion Bearing Removal
  • Slide 38
  • Spigot Bearing
  • Slide 39
  • Removing Power Divider
  • Slide 40
  • Power Divider Dowel Pins
  • Slide 41
  • Power Divider Assembly
  • Slide 42
  • Interaxle Differential
  • Slide 43
  • Measuring End Play
  • Slide 44
  • Pinion Bearing Cage Assembly
  • Slide 45
  • Check Pinion Bearing Preload
  • Slide 46
  • A Tool to Check Rolling Resistance
  • Slide 47
  • Checking Rolling Resistance
  • Slide 48
  • Drive Pinion Depth Controlled by Shim Pack Thickness
  • Slide 49
  • Pinion Cone Variation Number
  • Slide 50
  • Determining Shim Pack Thickness See Figure 24-59 on page 732 of the textbook.
  • Slide 51
  • Checking Crown Gear Runout
  • Slide 52
  • Check Crown Gear Backlash
  • Slide 53
  • Adjustments to Increase Backlash
  • Slide 54
  • Adjustments to Decrease Backlash
  • Slide 55
  • Crown Gear Tooth Nomenclature
  • Slide 56
  • Checking Tooth Contact
  • Slide 57
  • Correct Contact Pattern for Used Gearing
  • Slide 58
  • Incorrect Pinion Position
  • Slide 59
  • Incorrect Backlash Patterns
  • Slide 60
  • Adjusting the Thrust Screw
  • Slide 61
  • Summary (1 of 6) Adhering to OEM-recommended lubrication schedules is the key to ensuring the longest service life from both drive and dead axles. Knowing the correct procedure to check lubricant level is essential. The level is correct when lubricant is exactly level with the bottom of the fill hole.
  • Slide 62
  • Summary (2 of 6) Because most OEMs approve of the use of synthetic lubricants in final drive carriers, lubrication drain schedules have been greatly increased in recent years. Drain schedules are determined by the actual lubricant used and the type of application to which the vehicle is subjected. Servicing of axles on heavy-duty trucks consists of routine inspection, lubrication, cleaning, and, when required, troubleshooting and component overhaul.
  • Slide 63
  • Summary (3 of 6) Failure analysis is required to prevent recurrent failures. Drive axle carrier components usually fail for one of the following reasons: Shock load Fatigue Spinout Lubrication problems Normal wear
  • Slide 64
  • Summary (4 of 6) Most differential carriers are replaced as rebuilt/exchange units, so the role of the technician is, more often than not, to diagnose the problem and then, if necessary, replace the defective assembly as a unit. The technician who has disassembled and reassembled differential carriers should find troubleshooting procedures easier to follow.
  • Slide 65
  • Summary (5 of 6) Follow the OEM procedure when disassembling differential carriers. Taking a few moments to measure shim packs and gear tooth contact patterns on disassembly can save considerable time when reassembling the carrier. A crown and pinion gearset often can be reused when rebuilding a differential carrier. Make sure you inspect it properly on disassembly.
  • Slide 66
  • Summary (6 of 6) Crown and pinion gearsets are always replaced as a matched pair during a rebuild. When setting crown and pinion backlash, it is increased by moving the crown gear away from the drive pinion, and decreased by moving the crown gear toward the drive pinion.