Long story short after swapping my 2.8 12v with 140k miles for a 2.8 12v with 60k miles because the car overheated and blew a head gasket, and then blew the head gasket 2 times after that. The new engine runs perfect except now I'm having problems with the transmission. I have a diagnostics computer that is giving me an error code "torque converter clutch error". The transmission shifts iratically and when in over drive slips. If I place the shifter **** in "4th" the transmission shifts okay but of course there is no over drive, something still isn't right. The transmission never gave me any problems prior to the swap.

 

That sucks.. Auto tranny problems are always a bitch.. Its never as easy as troubleshooting bad synchros, or a clutch etc. It usually means rebuild/replace time. How long has it been since the engine swap? You should first call whoever did the swap and tell them whats going on and see what they say. But you somebody is most likely gunna have to take it appart to check it out, and after the labor it takes just to do that, you might as well find a low mileage used one, or look into a rebuild or something. Auto tranny problems are lose lose situations for the most part. Good luck...