"Kind of a gnarly buzzy sound that only comes
> with a big load at low speeds and low RPMs...So if I punch it in 2nd gear at
> 15+ mph...smooth acceleration only...But if I am on a sharp incline and
> going say..2-5mph and hit it,  I get that 'bridge-deck buzz' until I gain
> speed or lessen the acceleration.  It does not seem to be
> clutch-related...It happens after the clutch is fully engaged, or even if I
> decelerate in gear without using the clutch and then give it the pedal...

Have you checked to see if you have loose or broken engine mounts?
bob