Ok here is my predicament. I am swapping an LS1 and 4L60E into my '91 Trans Am (originally a 305 / 700R4) I bought the engine locally and the trans from a classifieds ad online nearby. The 4L60E was not from an fbody, it looks like a GMPP trans. It was basically brand new never used. Came in the crate. Anyways, I swapped an LS1 fbody tail housing on already, and put the trans in the car, got the swap pretty much all buttoned up. Anyways I am putting the driveshaft in and realize that it isn't even touching the output shaft on the trans it is so short. (The output shaft) Why I didn't realize this earlier I have no clue and it's my own fault.

But I want to know if the GMPP tranny's came with a different output shaft from the fbody unit?

If so can I swap it in the car?

I've been working on this car for months and really can't backtrack anymore. I am ready to just scrap the car and buy an LS1 fbody instead of a 3rd gen. Which would be thousands lost lol.

 

No sorry, it is too short I mean. It is so far in that when I installed the driveshaft it wasn't even touching the output shaft.

 

I hope it isn't a 4x4 trans, it has an orange plastic 2wd style tailhousing on it. From the end of the output shaft to the edge of the fbody tail housing is about 4.5".