5R55E rebuilt, still no reverse

[aut1jlt]

I've completed my rebuild of the 5r55e off my 2000 4.0L SOHC. Could not have done this without the 5r55e rebuild diary - THANK YOU, Glacier!! All hooked up to car except drivelines. Everything looks good in P, N, D, 1, 2. Backup lights come on in R, but the xfer case output is not spinning at all. Transmission was air tested prior to reinstalling, and all servos were applying/releasing. All valves were removed from valve body during rebuild, and Superior update kit, Ford separator plate w/gasket, and just the aluminum puck from the transgo kit were installed. Shift solenoids and TCC solenoid were tested and all OK - replaced EPC solenoid. No flashing lights on dash now . ANY IDEAS out there on why the output isn't spinning in R?

 

[Glacier991]

Hmmm do you have manual 1st gear?

 

[aut1jlt]

I believe so. My next step is to do the pressure tests. Perhaps I have a leak in the hydraulics somewhere. My other thought was the wiring harness in the valve body - maybe signal is not getting to solenoids?? Found a cheap hydraulic guage at Norther Hydraulics for $11 - with zero to 600 psi. I'll try that tomorrow.

 

[aut1jlt]

How do I tell? The transmission output shaft definitely turns in 1.

 

[Glacier991]

Follow your current path. In the way of war stories... I once rebuilt an A4LD that was installed elsewhere... the symptom on install was no reverse. I knew everything internally was ok, so I sent a new VB and all was well. When the old one came home I took apart the reverse valve bore and voila... I had misassembled it. Use that thought as your backup. Detail is critical and it is easy to miss one.

And yes, I screw up too. Keep me posted on your progress. In my case the reverse pressure would have been zero or nearly so.

 

[aut1jlt]

I had a chance to check the pressures, and found that at low idle in all ranges the pressures were about 5 to 8 pounds below the minimum acceptable range. But there was definitely pressure, which rose proportionately with increase in RPM. I did not go to WOT for stall test, due to the low initial pressure readings. The torque converter is new. Will look into valve body bores for reverse engagement, but think that perhaps without adequate pressure, the servo would not activate.

 

[Glacier991]

What was your line pressure in reverse ?

 

[aut1jlt]

Reverse pressure is 80 psi at low idle, 87 psi at 1000 rpm, 92psi at 1500 rpm and 94psi at 2000 rpm. Is this enough pressure to activate the servo piston? I really don't want to completely disassemble the guts again, but will if I have to.

 

[Glacier991]

The spec for line pressure in reverse is 175-215 psi at 1000 rpms... could be boost valve related.... something is not right. EPC in reverse should be 55-65 psi.

 

[Glacier991]

Mayber a better Q is to have you give me line pressures (and EPC?) in all gears....so we might diagnose better from there.

 

[aut1jlt]

RANGE Low Idle 1000 RPM 1500 RPM 2000 RPM
Park 73 77 81 81
Reverse 80 87 92 94
Neutral 73 76 81 82
Drive 72 77 80 82
2 73 77 77 81
1 71 76 79 82

The excel file doesn't copy and paste well here, but these are the psi readings taken. I believe I may have missed one o-ring. The "Fluid Pump Shaft to Inner Gear" O-ring is #10 on the ATSG illustration on page 8 of their 5r55e rebuild manual. Since this fits into the torque converter, I am not sure if this would affect overall pressure of the ATF or not.

 

[Glacier991]

The line pressures are definitely low.... in all gears... your suspicion of a missing seal is telling.

 

[BrooklynBay]

Did you use a In/LB torque wrench when you tightened the VB bolts? Sonnax has a boost valve, and end plugs with O rings to help with the line pressure issue.

 

[aut1jlt]

Yes, I used the in/lb torque wrench on the VB bolts. It is a very inexpensive one, but seemed to be working properly.

So you know how much the boost valve fix from Sonnax will raise the pressure? How many psi?

 

[aut1jlt]

When I pulled the reverse servo out today, it was VERY difficult to get out of the cylinder. How tight should the piston sit in this cylinder?? Is it possible that the double-lipped o-ring in the update kit is causing the piston to be too tight, and stick?

 

[Glacier991]

The hydraulics will move something that may to you seem tight... your pressures are low... the piston is unrelated to that unless it was leaking, which does not appear to be the case.

 

[aut1jlt]

I need to keep digging then.

 

[Glacier991]

If your fluid is clean (smile) I can loan you a new 5R55E VB to test with... with appropriate safeguards to make sure it comes home... you'd end up out of pocket for round trip postage and gaskets but it might help focus your energies.

 

[aut1jlt]

Glacier -
If I get to the ultimate frustration level, I may have to do that. But I still have some things to try first, like Bores 203,204, & 205.

The Reverse band appears to be in correct position, and when I put a small screwdriver down the Reverse Servo hole, it has a spring tension. So if I can get the servo to apply correctly, then everything should work.

 

[Glacier991]

Ok good luck... let me know how it goes.... did you find the Sonnax treatise on stripping the VB ? The stuff about using a wire to push from behind was a new one on me, and drilling in some spots blew me away, but it works!