Hey guys, I recently bought a project car, 95 pontiac formula lt1 with 38,000 miles, the was purchased as a roller, I bought the engine today, but before I buy the trans I wanted to see if only certain years fit...I know this transmission was used for many chevy vehicles and before I just buy a 4l60e trans I wanted to make sure I was buying the right one.

 

4L60E's aren't all equal- the V6 versions weren't as strong, may not bolt up depending on original engine. The heavy duty truck versions might work but may have a deeper pan. Possibly different torque converter and shifting characteristics based on application. 96+ OBD2 versions may require some wiring changes.

You would be well off to get a 94-95 V8 f-body 4L60E. Shouldn't be too hard considering how many people have dumped them in favor of a T56.

 

At some point (95??) they switched from switched TC lockup to pulse width modulated lockup. Your trans has to match your PCM.

 

Not to hijack, but I'd been meaning to ask about this. I have a spare motor and trans from my old 95 Z, both of which I plan to build to eventually replace the stock pieces in my 94 TA. How can I determine the lockup type with the trans out of the car, or can I at all? Also, if it turns out not to be directly compatible, what exactly needs to be changed internally?