4r55e with CEL p0761

[phix-]

Hey everyone,

Had an issue recently that I couldn't quite figure out. I think there are 2 available options to fix the issue but I wanted to see if any of the EF trans experts are still around.

Issue:
Code takes time to populate, maybe a day of driving. Maybe an hour, from what I can tell the p1000 never clears without tripping the code. I have all shift points and lockup till code is thrown. Then 3rd to lockup occurs. When the CEL is not present O/D off switch on the column works no issues. Various throttle positions do not cause the code to show up. Again once cleared the trans drives very well. Only exception is when going up an incline, I feel like there is some slipping. Very small amount, corrects pretty quickly code is not thrown after. Please also note, the O/D light is NOT flashing.

Parts:
- Rebuilt trans with maybe 6months on it, not alot of driving daily.
- New VB from CentralValveBodies
- New VB separator gasket
- New Solenoids
- New VB Harness
- 6qrts of Mobile1 Synthetic
- 2yr old overbuilt Torque Converter

Notes:
Fluid when newer VB went in did have some shimmer/metal flakes in it. That fluid was removed, not sure how much is left possibly 6qrts of less than 1yr old trans fluid.

Fixes:
I have read, this could be an O/D servo issue where the servo needs to be removed. Things need to be sanded some to allow the servo piston to move freely. Potentially not sticking open or closed. I have only read this through massive amounts of searching. Though I have just not found enough data to warrant that given the age of the rebuild. Any thoughts? Experience is greatly appreciated. Thanks in advanced.

 

[phix-]

On a particularly odd note. I threw a p0733 and o/d began to flash. What is so odd is I can also feel some vibration or shudder going into 4th. Anyone?

 

[JK080]

P0761 "Shift Solenoid C performance or stuck off"

P0733 "Gear ratio error in 3rd"


Check the overdrive band adjustment to make sure its no more than 2 turns out, then check the servo for the overdrive band. I have never had a problem with them sticking in the bore, they either blow out a corner of the seal on the piston or just become hardened over time and can't seal, its worth a look.

Some of these trucks in the mid 90's had computer issues, I have had to replace a few to get rid of these kinds of solenoid codes and gear ratio codes. If you can feel overdrive slip I would try to fix the slip first before thinking of the computer. The computers I have had to replace the transmission worked fine with no slipping.

 

[phix-]

After a year of hatred toward the p0761 I replaced my O/D piston. This was causing the p0761 code while having replaced the SS3.