One problem related to differential unit has been reported for the 2006 GMC Envoy. The most recently reported issues are listed below.
I was driving along interstate 69 near fort wayne in my leased 2006 GMC Envoy denali with my boss on company business when a car from behind me pulled along side honking their horn and yelling for me to pull over and get out of my car because it was on fire. We immediately stopped, got out, and saw flames underneath the engine compartment of my vehicle. We called 911 who dispatched fort wayne fire and indiana state police personnel. The car was towed to the local GMC dealership. Both a third party insurance investigator and a general motors investigator concur that the front differential failed causing lubricant to spray onto the catalytic converter and exhaust system igniting a fire. General motors has admitted to me that this is a defect I could not possibly known about nor was it my fault in any way. General motors wants to "repair" the vehicle and put me back in it. I've told them my life and my boss's life were at stake because of this fire which if no one had warned me about as I was driving, the consequence could have been two fatalities as I did not know the vehicle was on fire as I drove along the highway. I've asked general motors to do the right thing, break my lease, and they can have this Envoy to do with as they please. To date, they have refused to accommodate me. I refuse to put myself or my two small children back into a vehicle that was on fire and could have cost me my life!.