" ’97 GT cars should be steered clear from. If you plan to mod and have not bought one yet, don't. They use a very weak vacuum powered transmission (4T60E)."

Taken from the untouchable and undeniable http://www.grandprixforums.net/safel...0-a-67580.html

Your 97 is a GTP. It got the 4t65e.

I have a 97 GT. It has the vacuum 4t60.

Basically in 97 GM was extra stupid.