2-3 Flare in the5R55E

50 GEARS May-June 2003

2-3 Flare in the5R55E

STREET SMART

W elcome to Street Smart — anew column that’ll examinereal-world solutions to the

problems that face technicians everyday. Those of us who’ve been workingon automobiles for most of our livesknow that how we go about fixing aproblem might not always follow thetextbook solution. Because, when youget right down to it, textbooks don’t fixcars: Technicians do. And, in the realworld, we often find that following thetextbook only ends up leading us in cir-cles. That’s when we need to start think-ing… using our Street Smarts.

In this issue of Street Smart, we’regoing to look at 2-3 flare problems inthe 5R55E transmission. The 5R55E isa 5-speed automatic transmission,introduced by Ford in 1997. It’s usedwith the 4.0L engine in Rangers,Aerostars, Explorers and Mountaineers.

The 5R55E is mechanically thesame as the 4R44E and the 4R55E. Thedifference is in how the computer com-mands the upshifts (figures 1 and 2).I’ve been on the ATRA HelpLine fortwo years now, and in that time I’veheard problems with this unit nearlyevery day. Is it in the transmission?Computer? Wiring?… and so on. Onecall we seem to hear over and over is the5R55E with a 2-3 flare.

The call comes in like this:

“I have a 1999 Ford Explorerthat has a 2-3 flare. There’s acode P0733 (No 3rd Gear) inmemory. I’ve adjusted theEPC solenoid, went throughthe unit and replaced bothservo pistons, but I still have aflare on the 2-3 shift.”

by Mike Brown

Figure 1

Figure 2

Figure 3

Fig 1

Fig 2

Fig 3

52 GEARS May-June 2003

Figure 6

Figure 4

Figure 5

2-3 Flare in the 5R55E

Okay, let’s stop and look at what’sgoing on in the transmission. The sole-noid application chart (figures 1 and 2)shows that in 1st gear, only shift sole-noid 1 is energized, which applies theforward clutch. To shift into 2nd, ratherthan energizing solenoid 2, the comput-er energizes solenoid 3, applying theOD band. This actually overdrives 1st

gear.Then, to shift into 3rd gear, the

computer turns shift solenoid 3 off andsolenoid 2 on. So to shift into 3rd gear,the unit releases the OD band andapplies the intermediate band (figures3 and 4).

With that in mind, what could hap-pen that would create a flare on the 2-3shift? Unlike the 4R44E and 4R55E,the 5R55E applies the intermediateband for 3rd gear; not the direct clutch.At the same time, it releases the over-drive band. So if the OD band releasesbefore the intermediate applies, you geta 2-3 flare. The flare is a timing issue;the intermediate band is applying tooslowly.

So let’s recap on what we’ve doneso far:

1. We went through the unit. The for-ward clutch, direct clutch andcoast clutch all air check okay.

2. We’ve installed new servos, andnew intermediate and overdrivebands. The bands are adjustedproperly and air check fine.

3. Line pressure tests are withinspecs (figures 5 and 6). We evenbumped the pressure up a little byadjusting the EPC solenoid.

4. All shift solenoids are wellbetween 22–48 ohms of resistance(figure 7).

Let’s do more than just look at thevalve body; let’s disassemble it com-pletely. Take the time to flat sand thevalve body, making sure it’s nice andflat. This will help prevent crossleaks.Don’t just check the valves for wear,inspect the bores too, and make surethe end plugs fit snug into the valvebody.

An important point to remember is

that even if a solenoid has good resist-ance, it can still fail a functional test orleak test. If you don’t have the tools fortesting solenoids, you’re throwingmoney down the drain. With today’stransmissions, not having a dynamicsolenoid tester is like removing andinstalling a transmission using onlyhand tools, or without a lift.

We’ve had a lot of calls on 5R55Ewith a 2–3 flare and code P0733 (No3rd Gear). Code P0733 takes you topinpoint test A: Shift solenoid electricalcircuit test. Remember, this unit has 3rd

gear; the problem it has is a 2–3 flare. Most of the time it turns out that

shift solenoid 2 is leaking out the end,which delays the stroke of the 2–3 shift

Fig 4

Fig 5

GEARS May-June 2003 53

valve (figures 8 and 9). When the computer doesn’t see the RPM dropright after it energizes the solenoid, itassumes the unit didn’t shift into 3rd

gear, so it sets code P0733.Replacing all the solenoids during

a rebuild is one way to prevent this typeof problem. But it’s not really practical,due to the high price and lack of avail-ability of most solenoids. And remem-ber, just because a solenoid is newdoesn’t guarantee it’ll function proper-ly. The only way to be completely surethat all of the solenoids are workingproperly is to test them… electricallyand mechanically.

Testing solenoids is a sure way tosave time and money. It’ll help youtrack down many problems that don’tshow up using a typical electrical diag-nosis. And that’ll help keep you frompulling units a second time. That’s notjust smart… that’s Street Smart!

(See figures 8 and 9 on page 54.)

Figure 7

Solenoid I.D andResistance1. E P C 3.1-5.7 ohms

2. S S 2 22-48 ohms

3. S S 4 22-48 ohms

4. T C C 9-16 ohms

5. S S 3 22-48 ohms

6. S S 1 22-48 ohms

1-800-776-4433Fax: 1-856-222-4169www.wesellhardparts.com

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54 GEARS May-June 2003

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2-3 Flare in the 5R55E

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