Four problems related to noises during shifting have been reported for the 2002 GMC Envoy. The most recently reported issues are listed below.
My wife was driving our 2002 GMC Envoy onto a local expressway when she tried to accelerate, she heard a loud noise from the engine/tranny area, then noticed high rpms and the transmission not shifting, she immediately pulled over. I came to her location and noticed loss of reverse and a "whine" coming from the transmission, the vehicle was towed to the local GMC dealer, that same day it was diagnosed as the sun shell. It appears that this is a common failure, I will be pursing this further with gm.
Was hearing a clunking noise when shifting from park into drive. Eventually went to shift into drive and it felt like I ran over something, but nothing was there. Then the truck would not shift into second or fourth and lost reverse all together. Was told the transmission is blown.
On Dec. 3, 2003, I took my 2002 Envoy into the dealership because I was experiencing serious shifting issues. Repeatedly my car would shift while I was driving between 2wd and 4 wd hi. The car would also would make chugging noises. Furthermore, the vehicle shifted between gears on its own while I would be making sharp turns such as into a parking space. While in park, if I did not have my foot on the brake petal, the car would jump forward. The car almost jumped through a store front window. The dealer could find nothing wrong with my car. I told them to keep it another day, that there was something seriously wrong with the car. The dealer kept the car another day, and still found nothing. On December 31, 2003, I continued to experience the aforementioned problems. Knowing that it was new year's eve and that the odds of there being any competent staff at the dealer was slim, I held onto my car and planned to take it to the dealer after the holiday. On January 3, 2003, I was driving and my car died for no reason. I was not accelerating nor braking. Thank goodness the road I was on was not very busy as I would have created an accident. The situation was very dangerous and very frightening. I called roadside assistance to tow my car to the very dealer that could not find anything wrong with hopes that they would find something wrong. Roadside assistance, by the way, told me I needed a flatbed truck to tow my truck to prevent damage as did the dealer. Roadside assistance showed up without a flatbed - so I made them leave and bring back a truck with a flatbed. Two hours later, my car was finally at the dealership. The dealer flat out told me "I don't know if we are going to find anything wrong with your car. " apparently cars that stall in the middle of the road is perfectly acceptable for this dealership. The dealer told me he could not get me a rent-a-car for two days. The car is still at the dealership.
Transmission does not seem to downshift; loud fan noise with loss of power; hard shift into gear from start; missing rear seat latch to hold down seat and easily wobbles when shaken; hook for latch is present but no latch present seems to be design flaw.