One problem related to power train driveline has been reported for the 2003 GMC Envoy. The most recently reported issues are listed below.
My front differential started to seize up while driving on a major highway. My car would made a grunting noise and slowed to almost a complete stop, good thing it was early morning and the traffic was not heavy. A car or truck could of easily ran into my bumper causing me serious injury or death. I called the repair place right away and they got me in immediately. The diagnosis was the front differential needs to be replaced.