sporatic loss of OD and converter lock up

[Vetter]

Finally found the problem! Someone had changed out the transmission with another one, and the final drive ratio was the wrong one for the 3.4 engine, this was causing the VSS to read a wrong RPM and shutting down the TCC.

[Vetter]

Nope! That wasn't the problem!
Tranny guy gave me my money back, and said he couldn't fix it, now I have to start all over again!

[RednBlack]

Hey Vetter, I don't suppose you live close to Dayton, Ohio? I got one of the best tranny diagnostic mechanics around. He's a square deal guy too. Very familiar with the 4T60-E. (Mine). I'll call him and ask about your problem. Gimme a couple of days.

[Vetter]

No, I live by Grand Rapids, MI.
I would appreciate any help, I'm at a loss. The tranny guy, even put in a completely rebuilt different tranny than mine, and it still does the same thing. Keeps getting a PO740 code.

[RednBlack]

Got it. I'll print this thread and take it to him. Hope he can help.

[bszopi]

P0705 Transmission Range Sensor Circuit malfunction (PRNDL Input)
P0740 Torque Converter Clutch Circuit Malfuction

There are your 2 codes. Are no longer getting the P0705 code? It could possibly be a short in the wiring going to the tranny, hence the reason replacing the tranny with a new one didn't do anything. I'd check for any burns or melted areas in the loom for the harness. Or unplug the connector and check the resistance of all the wires back to the ECM. I think there is a diagram of the connector in the tranny section. If not, I can get one. Some may be a low resistance, but anything shorted directly to ground should read 0.

[Vetter]

No longer getting the PO705.
The tranny guy, went as far as bringing my car to a buddy of his, supposedly an "electrical guru", and this guy told my tranny guy, it was the gear ratio causing the code, and supposedly checked all the wireing, my tranny guy thought it would be a wire too.
I will try checking the wireing, for a short. I have a Haynes manual, which gives a good wireing diagram.
Thanks for the help.

[Quinky]

No longer getting the PO705.
The tranny guy, went as far as bringing my car to a buddy of his, supposedly an "electrical guru", and this guy told my tranny guy, it was the gear ratio causing the code, and supposedly checked all the wireing, my tranny guy thought it would be a wire too.
I will try checking the wireing, for a short. I have a Haynes manual, which gives a good wireing diagram.
Thanks for the help.

Gear ratio is impossible on a 4T60e... The gear ratio has nothing to do with the electronics of a 4T60E... ONLY a 4T65E does gear ratio matter...

Does your mechanic have a trans tech.. It's a computer you can hook up to the transmission... The transmission is run off the trans tech, not the car computer.. If everything works fine then you have a problem out side the transmission.. if not it's an internal problem..

[Vetter]

Finally got my car fixed, brought it to a different tranny shop, and they found the gear ratio, and sprockets were the wrong ones for the 3.4. Causing the computer to cut the lock up off, because it was at a too low RPM while cruising.