Hello, I've recently become the new owner of a 1987 Cutlass Ciera. It has the 2.8l v6 and I believe a TH125c (later called the 3T40?). Could I swap a 4T40 transmission into it for the automatic overdrive? Would it have any benefits as I'd be doing a mix of city and highway driving, or am I just way in over my head?

 

That transmission was used in later model, so it will fit. There might be a difference in engine cradle design, and almost certainly trans mount changes. Find a 4T60, avoid a 4T60E which would require countless wiring and computer changes. I’m sure it could be done, just a question of how much effort and money you want to invest

 

The TH125 is not computer controlled (other than the solenoid valve for converter lockup). The 4T40/4T45 are both computer controlled, which means that you need a stand-alone trans controller to operate them. They use computer-controlled solenoid valves to shift (the TH125 uses fluid logic in the valve body to control shifting). Unless you are prepared to spend a boatload of money swapping harnesses and ECUs, and having the ECU custom programmed for your application, this is a bad idea.

 

Thank you, I had misread that there was a non-E version for the transmission. Would there be an easier option, or am I stuck with the 3 speed?

 

The only non-computer 4spd transverse AT made by GM was the 440-T4, which was later renamed the 4T60 (not to be confused with the computer controlled 4T60E). The 440-T4 was a factory option in your 87 Ciera, but I don't know if it was available with the 2.8 or only with the 3.8, meaning I don't know which bellhousing bolt pattern they have. They are a popular swap into Fieros.

http://www.nathanbittinger.com/fieroaddiction/4T60a

http://snowcloude.com/~banner/FIERO-4T60.html

 

Sounds like the 440-T4 does have the correct bolt pattern for the 2.8. Here's more info.

http://fieroinfo.com/howto/4T60_Auto...Conversion.pdf

 

Hah that's the one I was thinking of, just got them a little mixed up. Thank you for the help, I'll see what I can do with it.