[CobraEd]

Bob has an excellent point about any part of the engine/bellhousing/transmission touching the frame. He is dead on!! To take his thought one step further, is the tailshaft mount (transmission mount) centered properly so that there is full movement within the rubber. If you had to jam the mount in for any reason, or cock it in such a way that there is no free movement within the rubber, this will emulate the driveline touching the frame and send all of the small vibrations directly into the car.

Ed