I have a 89 GTA with an A4. The tranny's supposed to be original to the car. But the Speedo's doesn't seem accurate and it doesn't seem to act the same as other trans am's and iroc's I've experienced. It seem's like it would shift better in a truck or something. It doesn't seem to be programmed for performance at all. The stock 700r4 in my dads old police pkg caprice shifted way harder and always downshifted when you'd want it too. Is the vin on the tranny anywhere? Is there an application code on it? I think this tranny's getting tired and I want to have this info before i decide to buy another one or have this one rebuilt.

might not be the same one. or might just be gettin old which would make it not shift as firm and so on. You can lose alot of power through a dieing tranny. As far as knowing if it was original to the car i don't think there is a way you can really tell since there are really no records of it. Engine blocks were one thing. tranny's were another. Best bet if it is a 700r4 you could get it rebuilt and have it shift where and how you want and you can beef it up a bit. put a new servo in it and throttle valve and more clutches and such.. I am in the process of pulling my 700r4 to replace it with an 88 700r4 and rebuilding my 83' original. I have seen trannys shift nice and firm and 3 years later under hard abuse turn into much. I guess one way to tell if it is original (although not always accurate) is to check the transmission mounts. and see if those are original looking. Most people who replace those things put in nice poly mounts and such.

The vin is stamped into the tailhousing and/or the main case. This is true on the vette's so I assume it is also the case on f-bodys. I have 2 700r4 van transmissions in the garage. They also have vin's stamped in them. On the pass side of the trans, just above the pan gasket, is the other info. It tells the year, julian date etc.

vin isnt stamped on them on others

just date code and plant code and year and such

there are pages on the net somewhere that show how to decode tranny stamping codes


good luck

But to tell if it is the actual orignal transmissino may still be a bit hard. because even if it is the same date as the car that still does not mean the original was not swapped out for vvarious reasons.