Amazing what you find out when you open the windows... The droning is coming from the rear. I knew the axle shaft was popping some, but not THAT bad. I climbed underneath, took hold of the shaft, and it rattles up and down. Hopefully hasn't done damage to the differential. Found a good replacement from a local shop (used w/warranty) for $100. That's Sat.'s project.
Still curious about the engine shocks. What would a bad one do? It has a "clank" when you turn it off. Could that be it?