Three problems related to automatic transmission cooler have been reported for the 2003 GMC Envoy. The most recently reported issues are listed below.
I smelled something burning after I parked my 2003 GMC Envoy xl in the garage. After inspecting, noticed transmission fluid leaking on ground. Towed to mechanic. Told transmission cooler hose was laying next to catalytic converter - not secured. Heat from cc rubbed hole in tc hose and therefore could have ignited vehicle. Since I had parked in the garage, it also could have burned my other vehicle and our house. Mechanic replaced hose and secured. GMC will not acknowledge this is a problem since I did not take it to a dealer for repair and they cannot find any recall or bulletin on this problem.
Our Envoy service engine soon light came on and then our Envoy would not go past second gear. We took to GMC and was told that the transmission had to be replaced. They stated that the upper coolant line had been touching catalytic converter and caused all fluid to leak out causing the transmission to fail . We saw no fluids in driveway or smelled any strange odors.
2003 GMC Envoy with a list of problems ** the consumer began to hear a knocking and pinging in the engine on cold starts and felt a hesitation when the automatic transmission shifted into gear. After many complaints, it was finally discovered the engine knock was due to shorter pistons in the re-designed engine and the hesitation in the transmission shifting required reprogramming. The consumer was told he would have to live with the engine knock, because it could be more trouble taking the engine apart. On a separate occasion, the engine stalled due to the battery dying. From April 2004 to October 2004 the battery failed several times and had to be re-charged. During that same time the engine light illuminated and each time it happened, the dealer would have to reprogram the engine computer. The radio was not functioning properly which primarily consisted of static. The driver information center control knobs as well as the radio knobs wore out. The front center console was loose. It was discovered that the engine light was coming on because the third stop light that's on the top of the liftgate malfunctioned. There was a short circuit in the stop light. The cooling fan broke, the brakes and the left front head lamp had to be replaced. The rear tail lights, directional and signal lights have been replaced several times. The lug nut broke while a replacement tire was being mounted on the vehicle. The front stabilizer linkage was replaced. The gas tank had to be replaced along with the fuel lines and a seal on the tank due to a leak. The seat belt was designed poorly and the belt cuts into the consumers neck. The drivers side door didn't close properly, the windshield wipers were replaced within the first 2 years.