Trans is TTA same as GN ?

[BradWE4]

I was wondering if they were interchangeable or if there was some special diffrence between them that made the tta's specific to the tta cars such as a special valve body or a special plate on the side?

 

[TTA850]

Other than the speedo these trannies are interchangeable.There are differences like the buick has a brf while the tta has a taf,also the tta trans has some valve body mods to make it go into and out of gear easier.

hth,
Steve