hello everyone...I just bought a 91 serria with a very noisey rearend,,a loud howling sound ,and had rear end ring and pinion checked by a cert mech,he says they are good,,noise is bad when acellerating and quiets when coasting..any ideas?...

 

Bearings?

 

did your mechanic check the back lash on the ring and pinion? That could do it too along with bearings