Back in 2020, our 2017 Yukon Denali with the 8-speed transmission started to shutter badly like others here. We took it into the dealership for service where they replaced the transmission valve body. After getting our yukon back, we started to experience a throttle/transmission issue. For example, when coming to a complete stop at a traffic light or stop sign, with your foot on the brake, transmission still in drive, the engine will rev on its own to 3,000-3,500 rpms and then bang into first gear, lurching you forward. At this point, you're stuck in first gear as you pull away from the traffic light or stop sign... it will not shift out of first gear regardless of your rpms. At this point, we pull over to the side of the road, shut the engine off, wait a few minutes and restart the engine. At this point, we can put the yukon into drive and it will shift through the gears normally, however, the "check engine light" is on. We've taken it back to the dealership a few times and they have reflashed the computer, replaced the valve body again, fluid, etc. It did it again today after getting the yukon back from the dealer a few days ago. Now they want to tow it to the dealership again. Has anyone else experience anything like this where your vehicle's engine revs on it's own? My wife's afraid to drive it for fear it's going to launch her into an oncoming vehicle. She says it acts possessed. LOL!
2017 GMC Yukon Denali Transmission / Throttle Nightmare
- Thread starter csmpez
- Start date
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It started with the transmission shutter... that was really bad. After the transmission fluid and valve body replacement (this was done twice), it started this crazy behavior with the revving and "neutral dropping" into first gear scenario. Dealership had our yukon towed to them with a loaner waiting for us. Curious what GM will say this time around.
Maybe an electrical short causing it? I had a transmission once that would do weird things until it finally locked up. Transmission shop swore it was my computer and I told them it's something in the transmission. Once they swapped it for a rebuilt one it ran like new. Something in the electronics of the transmission was wrong.
