Chevrolet: rear end whine, chevy caprice, caprice wagon

Question
92 chevy caprice wagon 350 auto i think 8.5 rear end. When i bought it i thought it was tire whine, it wasn't. We pulled the axles & replaced the wheel bearings & seals. It didn't change anything. Cousin said he had a van(of that vintage) that did the same thing & was told by dealer that some just do that. Its not a posi rear. What can we try next? prior owners records indicate carrier bearing were replaced @ 50k miles ago.

Answer
You could try having it diagnosed before you just start throwing parts at it. Without hearing the noise I cant tell you where to start. It could be a pinion bearing, side bearings, ring and pinion wear, or just not set up correctly. All rear ends will make some noise because they are gears that mesh together. Most will only do it in a certain speed range like only between 30-40 or 65- 75, etc.
Vans are usually worse because the box of the van acts like a speaker cabinet and amplifies the noise.