hi guys. my name is robert and i'm new to the forum. my problem is the rear end on my 1999 suburban is making a loud roaring sound. i'm thinking the diff is shot. i'm about to take off the cover and check for meteal particles/visible damage etc. is rear end failure common on these trucks? i'm a pretty good mechanic, but i've never rebuilt a diff. so, i'll be scouring the salvage yards looking for a bolt in replacement. aside from low mileage, and particular options, what should i look for as far as picking up a good replacement? in other words, how can i determine if the new diff is damaged before i buy it? thanks for any help that i can get. i'll post back with what i found in my diff.