Yup...the Suburban's. Under warranty, but nonetheless a pain in the *****. The diff's for the Avalanche and 'Burb are the same. The Avalanche was no longer under warranty so that prompted me to protect it first with the Mag-Hytec and Amsoil Gear Oil. The Mag-Hytec holds more than a quart more gear oil than the stock diff cover which really helps out too.
The guy at Chevy told me the same thing about the rear-ends on the Suburban's going out too soon. Problem is he wouldn't say that after warranty runs out, he would simply say, Cha-Ching.