I own a GMC Envoy XL, 2003 model. Purchased it new and have driven about 108,440 miles. Recently, I noticed that when shifting from 2nd to 3rd, it takes a longer time, and causes the rpm to climb up to 4000 to 5000, thus resulting poor distance/mileage ratio. The dealers want me to replace the entir transmission. This is an automatic transmission. It will cost me over $3800.00. Is it probably A sensor problem? Please advice me. Thanks. Joe
It sounds like the dealer is giving you the straight poop on it. It sounds as though you are having a hydraulic leak in the 3-4 clutch. The leak is causing the clutch piston not to clamp down on the clutches and this is where the slip is coming in. The leak could be anywhere from a bad sealing ring on the turbine shaft to a leaking 3-4 piston in the input drum. If this was a sensor issue such as a pressure control solenoid you would be having issues in other forward gears also. You are going to need to replace/rebuild the transmission.
transman
Joe, I just reread your post and realized I forgot to ask you something. You said that the RPM’s are climbing to 4k to 5k. When the RPM’s climb that high does the truck feel like its not going any faster? If the trans is still pulling at that rpm and it just feels like it doesnt want to shift then you might want to get a second opinion. I would scan the computer to see whether the computer is commanding the shift. In this case there could be an electronic issue like a TPS reading high.
Sorry, I should have mentioned this first in my previous post. I was getting ahead of myself.
transman
If I start off faster, the !st to 2nd Shift is normal, the 2nd to 3rd shift just continues without shifting to the third shift whiles acellerating with the engine pitch going higher, and the rpm keeps climbing as if I were racing. I have to ease off or release the accelerator (gas) peddle, then I can hear gear shift to 3rd ( it is also indicated by rpm dial moving to lower revs). I Have a strong feeling that computer controlling the the shift commands is faulty and that the dealers are want to make more money from me by telling me to get new transmission. Once the 2nd to 3rd is made, then to 4th and eventually overdrive is not as bad and truck can go past 85mph without a sweat.
Ok, then I would start looking at electronic issues. I would get a second opinion and have it scanned to see whether the computer is commanding the shift at the right time. It still could be a hydraulic problem requiring an overhaul but some dealerships and even trans shops are quick to say “replace it” or “rebuild it” Rule out a sensor problem first. Let us know what happens.
transman