Two problems related to transmission noise have been reported for the 2003 GMC Envoy. The most recently reported issues are listed below.
Dear sir/madam, I have a 2003 GMC Envoy slt model 4. 2l v6 4wd and as I was backing into my garage I heard a loud bang and whinning noise and I now have no reverse gear and when I select the drive gear on the automatic transmission I have a whinning noise, I have read the blogs on this issue and I believe that gm and GMC are very aware of this problem, this repair will cost me up to $2,800. 00 plus tax to have the transmission removed and a remanufactured on replaced on my vehicle. I was just glad that this matter happened at my residence and not on some back road in west va. , I believe that as stated, gm and GMC is very aware of the problem with the 4l603 transmission that were used in these vehicles' and the problem with the sun-shell and the reaction sungears that are like a gernade exploding inside the transmission. I would like for a recall to be started on this problem and the owners to be paid back on all of these repairs.
My 2003 Envoy with 68,000 was rear ended. Shortly after the accident I began to hear a cluncking noise when stopping. After I took the vehicle in to be repaired I was informed that it no longer would go in reverse. The problem appears to be the sunshell gear which seems to be a common failure with this transmission, because even though it was fine before the accident the dealer is claiming it was not caused by the accident and thus I am responsible for the estimated $2,500 to fix!.