I've got an '01 GMC 2500HD 6.0, auto with I think a 10.5" 14 bolt rear end, 4.10 gears, w/ 140K. Just got back from a long trip pulling a 24' trailer with camper in the bed, the last couple of hundred miles I noticed a roaring or grinding noise coming from the rear end. Opened it up, I have a little experience with rear ends but not much, replaced the small brg on the pinion shaft as it seemed a little sloppy, the other brgs. on the pinion seemed fine and the chunk spun freely with little noise with the axles out. Put in fresh oil and still have the same noise, btw it is a limited slip.
Anyone got any ideas as to where I go next, thanks for any help you may have.

Dan

 

Have you checked the wheel bearings?

At 140 they may be giving it up?

jvp