PO770 Error

[MattInLA]

Hi, my transmission for my 96 was rebuilt, car rides excellent, however getting these 770 errors usually when going up a hill, my shop replaced the valve body, all sensors good, car rides with no issues, he maintains it's a CPU issue anybody have any other ideas what I should do.

[ShawnM]

The trans was changed, but was the torque converter changed with it? Were you getting these codes before the trans was done? Is everything stock or do you have aftermarket mods?

[MattInLA]

Yes transm. completely rebuilt new torque converter old one disintegrated no the error message was not there, I am having my suspicions the transm. was not rebuilt correctly feels like its slipping / using too much gas what is your take..........

[jetwhine]

Mattinla,

I would say since you just had all that work done, maybe a code has latched itself into the computer. Have you tried to clear the code? I would try that first. Disconnect the neg. battery cable for about 1 minute and reconnect and see if the problem goes away.

[dandeman]

Specifically, the PO770 is pointing to a Shift Solenoid "E" Valve SL malfunction. This valve controls the torque converter lock up clutch function.

Error Detection Logic (for PO770) :
Lock up (torque converter lock up clutch) does not occur when driving in the lock-up range (normal driving at /above 50mph), or lock-up remains ON in the lock-up off speed range.

Trouble Area:
The possible troubles are:
1) Shift Solenoid valve SL is stuck open or closed.
2) Valve body is blocked up or stuck.
3) Lock-up clutch problem.

Reference: Factory Service Manual Volume 1

Hope you have a warranty on the rebuild...

It should be a simple road test (and watching the tachometer) to determine if lock up/un lock is occurring when it should...

[awmccready]

What is the "simple road test for lock up/un?"

I need to perform that test for my PO770 engine check.

Thanks.

[MattInLA]

Torque Converter Defective