This issue is outlined in TSB 06-04-114-001A. Known issue with the differential in the AWD models (not just Rendezvous, apparently). The initial fix, which they did on this visit, is to flush the differential fluid twice, then replace with a new synthetic fluid. If the issue comes back, the rear end housing has to be replaced. This is pathetic. Additionally, because we're out of factory warranty, we had to pay $185 for the flush. THIS IS A TSB!!!! It is a known design flaw in the vehicle, why are we having to pay for it??? I've had TSBs addressed in Acura and Mitsubishi cars I've owned, and never had to pay, even outside of warranty.

Honestly, stay away from GM. Their quality control has gone downhill in a bad way and they've done nothing to improve the situation. Save yourself the headache and buy foreign.