Driveline  Vibration Issue - Possible Root Cause

This  guy ran over a mattress and decided to keep going.  The ensuing jumble finally whipped around enough to  put a tear in the gas tank, the subsequent lack of  fuel is what finally brought this vehicle to its  knees.

It had still managed to drive 30 more  miles decently with a 60lb tangle wrapped around the driveshaft.

This genius complained that the  vehicle had a "shimmy" when driving it high  speeds.

This is what the dealership  found..............