SILVER LS4

I'd bet the rear end wasn't replaced, maybe the fluid a couple times then the center section. The common problem in the early ones was a groaning noise when turning at slow speeds. The cause was the limited slip clutches gripping too much. There was a couple of fluid type changes, then they came out with a diff center section if that didn't help. But maybe he did, however, the rear end in a TBSS is one of the strongest ones GM produces.

evil 5.3

It had the fluid changed a few times center section changed twice and the whole thing once before they trade it for a dmax