Man Al did you buy another cool Mopar ? I was thinking about the ball & trunion joint is possible if it only does it on the gas and stops off the gas or even the rear U-joint as most of the time drivetrain joints only vibrate bad when on the gas and you said it does it in all 3 forward gears. The only clutch that is applied in all forward gears is the rear clutch which could be a problem also. And dont forget I believe that trans uses a rear pump in 64. Ron