2021 GMC Yukon: complete transmission failure

Filed Oct 16, 2026 · Engine, Transmission · GA

Bought 2021 GMC Yukon Denali new. Transmission failed at 70,000 miles. Engine has now failed at 111,000 miles. Both diagnosed at Capital GMC Atlanta, GA. Cost to replace transmission $8k (GMC paid half). Cost to replace engine $12k (GMC offered no assistance). Engine failure not related to current engine recall/investigation on GMC 6.2L V8 engines. This failure was on the top vs on the bottom (current recall).

Filed Jan 13, 2026 · Engine, Fuel system · FL

I have a 2021 GMC Yukon with 74,000 miles I was recently told I need a new transmission.I am am trying to understand why a car that is 5 years with all the services done by Lehman GMC in North Miami would need a new transmission they have been servicing this car and no one mention anything breaking down of need of repair until now. I spoke with the service manager Franklin and he stated to me another client had the same issue and he flush the transmission just like I am doing today and it only worked for a short time and afterwards he had to replace the transmission. I feel this is a problem with these models and GMC don't want to address it. they just want the customer to pay for the repairs. Now I spoke to the Manager and the salesman that sold me the car and nicely told me he was sorry and he could get us out of this into a 2026. Now why would I buy a new car if they cannot get the 2021 right. I have included my invoice below I feel some one should look into this I feel this is a recall matter and GMC is trying to pass the buck. Thank You [XXX] [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Jul 8, 2025 · Transmission · TN

My Denali had no previous problems, I pull out of the driveway and I felt a hard Lunge forward without me pushing the gas. Almost like the car accelerated like a hard jerk. I pulled over because I thought I had been hit by another car. After checking no cars around, I pull back out and I felt it again a hard lunge forward. If someone would have been in front of me I would have hit the car in front of me without even pushing the gas. These GMC are dangerous and can’t trust my vehicle. After getting stranded on the road found out the transmission went out. My suv is now being repaired at GMC at my expense. Only had the vehicle 6 months. Recall the transmission.

Filed Apr 29, 2025 · Transmission · FL

I have had major transmission failure in my 2021 GMC Yukon Denali (6.2L V8, 10-speed automatic). The vehicle has approximately 72,000 miles. Recently, a critical internal clip/retainer in the transmission broke loose, sending metal debris throughout the transmission. This catastrophic failure has rendered the vehicle undrivable and requires a complete transmission replacement. Unfortunately, the vehicle is just outside the powertrain warranty, yet I firmly believe this failure is due to a manufacturing/design defect – not normal wear and tear. I purchased this Yukon Denali as a premium, flagship SUV and have maintained it carefully. I expected the transmission to last well beyond 72k miles under normal use. It is disappointing and that a core component failed so early. Not only has this imposed a significant financial burden, but it also undermines my confidence in the vehicle’s safety and reliability for my family. A modern transmission should not self-destruct at this mileage, especially given GM’s reputation and the Denali’s top-of-the-line status. Importantly, I have discovered multiple known issues and GM bulletins related to the 10-speed automatic transmission used in my Yukon. For example, GM issued a major recall in late 2024 (the federal safety agency Campaign 24V797000, GM recall #N242454440) affecting 2021 Yukon models (among others) due to a defective transmission control valve that could fail and cause the rear wheels to lock up, this demonstrates that GM has acknowledged serious problems in the 10L80/MQC 10-speed transmission design. Additionally, a recent GM service bulletin (PIP6008C, Jan 24 2025) indicates that internal transmission retaining rings can dislodge, causing the internal gears to separate – which leads to loss of reverse and internal damage. This scenario is similar to what happened in my transmission. My family was left stranded away from home with no warning. The vehicle just stopped working. The warning lamp did not come on until diagnostics was run.

Filed Mar 24, 2025 · Transmission · NC

Transmission failure at 72k miles.