LTxDave

On my 95 the torque converter appears to be trying to lockup, but it does not. About 60 mph, you can hear the engine speed vary slightly, but it never drops and smooths out. The RPM's are higher than what I'd expect with 3.07 gears and a lockup converter. The fluid is clean and the filter/fluid has low miles. The car and trans itself has 225k miles. Other than the converter locking up, the trans appears to be in good shape. Anyone have guidance on diagnosing this problem?

383vett

Your symptoms and mileage suggest a worn torque converter. There is a chance it could be your lockup solenoid in the tranny not working properly, but I would guess it's the lockup lining in the converter that is worn. If the tranny seems ok and you don't want to spring for a rebuild, just change the converter.

LTxDave

There was some wear material in the pan when I changed the fluid, but it did not appear to be excessive. Going through the factory manual, it pointed to the lockup solenoid but my experience with other types of solenoids is they work or they don't. I really think if I'm going through the trouble to pull the trans again that I will go ahead and rebuild it. Thanks for the help.

engle1147

You may want to check the adjustment/contacts on brake switch. An intermittent brake switch can cause your tranny to drop in and out of lockup. Here is a good thread that shows the switch in a little more detail: http://forums.corvetteforum.com/c4-t...-for-94-a.html

blue94

Had the same issue with my 94 but a lot less miles. I did a Datamaster log on the tranny and saw the ecu send the command but nothing returned to say it locked. Replaced the lockup solenoid and all was fine.

If the solenoid sends a lock confirmation back and converter still not locked look at the TC.

LTxDave

Thanks for the other two suggestions engle and blue. I was looking at the wiring schematic and wondered if the brake switch could cause a problem like that. Also a good idea to datalog and see what is happening.

Thanks again!