Having problems with your 2002 GMC Envoy ?
2002 GMC Envoy transmission problems
\015 Just got a 2002 Envoy that has been parked for 2 years. The transmission was slipping so I changed the filter and fluid, doesn't slip now, but the only way it will shift is to back off the gas when the revs go up and step on it again to change gears. But it only works in A4WD, the lights flash for 2hi but it won't go in. Also there are 2 plugs unplugged and all corroded that plug into a box under the drivers door attached to the frame with what looks like brake or transmission lines coming out of it. Could this have something to do with the problem?\015
Since the truck sat for so long, I suggest checking the operation of the detent cable and linkage at the transmission. It is common for the linkage to stick due to corrosion from sitting for a long period of time. I had the same problem with my Jeep GC. There is a small return spring that is not strong enough to pull the linkage back if the linkage does not move freely. I suggest using AMSOIL penetrating oil if you cannot move it freely in BOTH directions. I sprayed mine and let it sit before it freed up. Shifts like a dream now. The transmission works the same in 2wd or 4wd. It seems you have a seperate problem with your transfer case.
Repair Help & Product Troubleshooting for 2002 GMC Envoy
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