(2)Drive shaft center bearing

[Doyt W. Echelberger]

Just an afterthought...........It may be some other drive shaft, like a 
drive axle, and it may be some other component contacting it. Lots of 
clearances change when you back off on power, and there are lots of 
suspension bushings that could have failed, other than the tranny mounts.
So much for second thoughts.           Doyt