GM-GMC: car trouble, buick park avenue, autorecycler

Question
Is a 2000 GTP aka pontiac grand pre transmission compatiable with a 2002
buick park avenue ultra?

Answer
That is a question that an autorecycler or a dealer would be better suited to ask.  The Grand Prix is a W-Body car and the Park Ave is an H-Body car, but they could share a tranny.  Phone a junk yard and ask them to cross reference it for you.
Hope this helps