If there is a thread for this please let me know. 94 ts auto mpi

For some reason my car (when in overdrive) changes down one gear and back up constantly. With o/d off the car runs fine. I've tried a reset ( bat terminals off) still no difference. Replaced the overdrive clutch about 3 months ago. This only started happening about 2 months ago (she overheated on the same day due to a dodgy thermo) Could my TCU be shagged? Also could a buggered TCU be draining my battery?
Thanks Guys.

Next time this happens, with the O/D switch in the on position, depress and hold the switch and see if it remains in 4th and no longer intermittentently engaging.

I've seen someone get charged $2000 for an O/D issue and gearbox O/haul in a Lancer back in the 90's, after taking it back for a "stronger circlip" problem still there the lady gave up too embarrassed to tell her dad. I took it for a drive one day and no bull it was simply the O/D switch and when pushed 4th was perfect. And that was a RACQ approved repairer.

worth a try and will cost nothing if I'm wrong.

another thing I was thinking, it's definitely going back to third and not just a case of the torque convertor lock up clutch releasing?

TW2005 may be on the right track. Are you sure it is really changing up and down between 3rd and 4th gear or is it the lock up clutch engaging and disengaging?

I have just had the lock-up clutch problem with my 1st gen. TP sedan. According to your profile, your have a 4 cylinder TS. If so, the transmission is the same as the TP, so have a read of my post #5 in this thread: http://www.aussiemagna.com/forums/showthread.php?t=102085&page=1

I'm not sure the transmission wiring colours are the same between TP and TS but the transmission temperature sensor and the way it operates is definitely the same. If you can identify the wiring from it and find its connector (it should be the only 2 pin one), then just undo that connector and take the car for a drive. If the hunting up and down no longer occurs, your problem is the lock-up clutch, not the overdrive.

Thanks Peeps, will get back to you on the outcome.