GM 4T65E Tranny Problem

[Ryan00TJ]

Mother's 98 Monte Carlo Z34 got this code a few days ago and the car is hardly driveable. Upon startup it bucks and stalls and shakes. The code revealed to me was PO742.....Torque converter clutch circuit stuck on......

What does this mean? Sounds like the torque converter is stuck locked. Does the transmission need rebuilt or is it simply a solenoid gone bad not allowing the converter to unlock?

Thanks for any help!!!

 

[T-Keith]

Sounds like the TCC lockup solenoid is stuck. The only good solution is to replace it. For this you must remove the side cover of the transmission.

-T

 

[FazerZ]

It depends on which transaxle is in the car. The 3 speed automatic (3T40) has trouble with the TCC solenoid sticking closed and causing stalls. It's a relatively easy fix of replacing the solenoid as suggested earlier.

If the car has a 4speed automatic (Overdrive present), then the scenario changes quite a bit and it is very unlikely the TCC solenoid is the cause of the trouble. This diagnostic steps for this sort of repair on the the 4speeds (4T60E) are not DIY. Take it to a good transmission shop for the proper work.

Good Luck.

DH

 

[T-Keith]

He said it was the 4T65e in the topic.

I've changed the TCC solenoid on the old 3 speed, it's an easy fix. The only difference I see on the four speed is that you must remove the axleshaft before taking of the side cover.

-T

 

[FazerZ]

I should learn to read the topics better!

Given the details, I would make the same recommendation as if it were a 4T60E. It's highly unlikely this is being caused by JUST a faulty solenoid. The side cover can be removed in the car, but again this is farily tricky to do and beyond most DIYers.

I think you would be best served by a good transmission shop to pinpoint/diagnose/repair.

Sorry for the confusion.

DH