Originally Posted by TwinTurboGTR

Ok,

Have someone help you with this then. Place in drive, hit ebrake and someone smash on the brake and throttle the gas. If you see excessive engine movement, then the mounts are shot.

I may be picturing it wrong, but it sounds like the vibration might be from the main pulley. While you are there, check to see if the VD is spinning true and not all gobbadeal.