I've known for a couple years that I had a bad axle seal on the right rear (pass. side). Just noticed today loud whine on decel that goes away with acceleration. It sounds like its coming from the right rear.

Its like a whine and mild grind sound combined. I think its my bearings...I just wanted to be sure before I replaced them.

If it was a driveshaft vibration problem (or U0joint), how would I know?

 

Have you ever added fluid to the diff to replace the missing fluid? What you describe sounds more like a problem with the coast side of the ring and pinon.

If it was a u joint problem, the joint would most likely be loose. A drivshaft balance issue would cause a vibration independantly of whether you are accelerating or decelerating.

 

As it turns out...its my pinion bearings. And the teeth on my internal gears are a bit chewed up also.