No Third Gear + Tons of DTCs 4r55E - '95

[rob2337]

All right, it has been over a year since I have had transmission problems. The last problem was a TC lockup when it wasn't supposed to resulting in the truck stalling at every stop. I finally solved this with an ebay valve body and internal transmission wiring harness.

Now the revenge of the 4r55e....

My girlfriend borrowed the X, when she returned it, she said it was louder than usual and the OD light was flashing. I took it for a test drive, and from what I can feel....No third gear.

The symptoms are as follows:

Shift from first to second easily, but going around 35mph, the tach still climbs. No 3rd shift.

This is the strange part, once i get up to around 40mph, the torque locks up and the RPMs drop to like 1200 RPM with the engine chugging along. It releases if I give it some gas or brake.

Pulled the codes and I got:

DTC 636 - Key one engine off - Trans Temperature out of range, Probably because it is below zero here....not big deal

DTC 639 - Continuous memory Turbine shaft speed sensor error
DTC 646 - Continuous memory 2nd gear failure
DTC 647 - Continuous memory 3rd gear failure

No bad noises at all coming from the transmission, shifts smoothly except into 3rd. Any chances it could be just a bad shift solenoid or bad connection on the transmission wiring harness?

Would a broken band create the following symptoms. I know there is a stall test to try to eliminate band problems, could someone elaborate on this?

Any other ideas?

Thanks

 

[Glacier991]

Your choices... the main ones... either relate to the SSA and SSB solenoids having issues, other possible VB issues, and/or a bad direct clutch.

In the 4R the 2-3 shift is caused by the intermediate band RELEASING, and the direct clutch being applied. No band issues in this problem.

My guess? Possible blown out VB gasket in the Direct clutch circuit.

 

[rob2337]

OK so it should be a valve body / solenoid problem. Not a $$$ rebuild the whole thing problem. I know the 4r55e had a overpressure problem. One quick question, when I changed the valve body last year, I also changed the wiring harness. I noticed that the connector on the EPC solenoid had a built in resistor. Is this to lower the overpressure problem? If so, I put a new gasket in when I swapped valve bodies, the likely hood of the gasket blowing out would be low, right? Unless I somehow messed up the torque pattern or the torque on the valve body (always a possibilty).

So to start working on the problem:

1- drop pan and valve body

2- Inspect gaskets and look for a possible blow out area. (is it easy to tell like a head gasket)

3- If no obvious blow out, install new gaskets, maybe swap out shift solenoid with old ones I have from previous valve body.

4- Carefull install bolts in proper locations, and retorque in proper sequence.

 

[Glacier991]

S'what I'd do. I think that is a cheap attempt at a fix. I'm keeping my fingers crossed.

 

[rob2337]

One last question. If there are no bad noises coming from the transmission, and I don't push it. Would it be okay to drive it for max a week untill I get the parts and time to open it up? Or should I park it.

 

[Glacier991]

How far are you driving it ?

 

[rob2337]

Not on a road trip, just around town like 20 miles over the next week.

 

[rob2337]

Are there any other valve body gaskets other than the ford ones, which seem to have a history of blowing out?

 

[rob2337]

**** Update*****

Ok I have not dropped the pan and changed the body gaskets yet, but I took the X for a drive and played with it.

Foresure no third shift.

Also when I press the OD off button, the transmission seems to shift "into a really low gear" or has "a super high stall" basically when the button is pushed, in any gear or at any speed, then X just starts crawling, and I have to rev it to get moving.

So can this still be a blown v body gasket or do I pull the transmission.

thanks for all the help

 

[Glacier991]

Until you have pulled the VB and done evrything possible there, I'd definitely NOT pull the trans. Btw the resistor on the EPC is an attempt aftermarket to UP the line pressure it is trademarked as the "Pressure Riser".

 

[BobK]

What is the correct resistance on the resistor inside the EPC connector?

 

[XR250rdr]

What is the correct resistance on the resistor inside the EPC connector?

Varies by temperature, link below is the resistance chart.

http://www.xr250rdr.com/upload/files/1/TFT Test.pdf

 

[BobK]

Forgive my ignorance. I've seen other references to connecting the Transgo resistor to the EPC circuit to adjust pressures, so I'm confused.

The little resistor inside the EPC connector is the Transmission Fluid Temperature sensor?

 

[XR250rdr]

Forgive my ignorance. I've seen other references to connecting the Transgo resistor to the EPC circuit to adjust pressures, so I'm confused.

The little resistor inside the EPC connector is the Transmission Fluid Temperature sensor?

Yes, the resistor (a thermistor actually) on the factory harness is the TFT.

The EPC pressure riser from the Superior kit clips onto the EPC leads with vampire clips.