hard shifting into reverse from park????

I have a 1999 grand prix gtp with 75,000 miles on it. I am having an issue with the transmission....It shifts great while driving, but when shifting from park to reverse or neutral to reverse it really shifts hard and the engine moves alot. Shifting into drive does not clunk as badly as reverse.

I rotated the radiator support bushings at the top of the engine but the engine still wants to move alot during the reverse shifts.

Would it be a bad motor mount or transmission mount? Would it be from having too high line pressure inside the transmission?