2020 GMC Yukon XL: sudden loss of power

Filed Sep 21, 2026 · Transmission · MO

The transmission failed on August 8, 2026, while I was driving on a highway. I moved safely to the shoulder, but the vehicle became inoperable and required towing. The loss of propulsion in active highway traffic created a potentially hazardous situation. My GMC Bommarito Buick GMC dealership advised that GM cannot currently supply the required replacement transmission. The dealer has no estimated delivery date and does not know when GM can supply the unit. The vehicle has been out of service for over four weeks, with no definite repair or return-to-service date. I am concerned that the inability to provide a replacement transmission may indicate unusually high demand or a broader issue. I identified other recent the federal safety agency complaints involving 2020 GMC Yukon XL vehicles reporting 10-speed transmission failures and difficulty obtaining replacements, including ODI complaints 11711773 and 11747021. I request that the federal safety agency evaluate this complaint with similar reports. I respectfully request that the federal safety agency consider whether: • These transmissions are experiencing premature or unusually frequent failures. • Valve-body, internal, or other component defects may contribute. • Failures can cause sudden loss of propulsion, unexpected shifting, loss of power, or other safety-related conditions. • The replacement-transmission shortage is connected to an unusually high failure rate. • GM has sufficient replacement units and repair components available. • Available complaints, dealer information, and manufacturer information warrant further investigation or action. I request that this complaint be associated with my VIN and reviewed with other complaints involving 2020 GMC Yukon XL Denali vehicles and other GMC, Cadillac, and Chevrolet models equipped with the 10-speed 10L800-speed automatic transmission. I believe the circumstances warrant review as a potential broader vehicle-safety issue, rather than solely an individual parts-availability problem.

Filed Feb 22, 2026 · Engine · CO

My 2020 GMC Yukon XL Denali 6.2L with 59,000 miles developed a ticking noise and slight power loss diagnosed by three different garages as a "collapsed lifter" on #4 cylinder. It's one of the AFM/DoD cylinders that shuts down to save fuel. $8,000 repair estimate, or $12,000 if the failed lifter damaged the camshaft. All three garages said "we see a lot of these." Internet forums are loaded with lifter problems on this engine: specifically AFM/DoD lifters. Safety is not affected. Noise/diagnosis reproduced by three independent garages. Has not been inspected by mfg, police, or insurance rep. No warning lamps or messages, no ODB2 "codes" found by garages. Seven months ago the water pump exploded on Interstate 70, putting us at serious risk. Now this lifter trouble at 59,000 miles. Both should have been covered by the 60,000 mile powertrain warranty, but I'm beyond the 5-year limit.

Filed Feb 20, 2026 · Engine · NM

Complete engine failure while driving on I25 in New Mexico, lost all power was able to roll into a airport parking lot. If I had not been close to the off ramp it could have been catastrophic with the truck traffic on the Interstate. The vehicle has completed all of its normal maintenance on time, and as of January 30, 2026 had a complete review from GMC that everything was in great shape including the engine. There was never a warning light, a maintenance message or any other indication.

Filed Dec 4, 2025 · Engine · IA

This concerns a 2020 GMC Yukon XL Denali motor (6.2L gas) 118,000 miles. Regular maintenance performed every 5 K miles and per request of original dealer. Beginning 2 weeks ago a new regular pinging developed and the vehicle was taken to the dealer (at which time new tires were installed routinely). No clear issues were found upon brief inspection/auscultation and advised to return if the sound was recurrent. The sound persisted on a fairly frequent though intermittent basis. A recording was made and another appt made for routine spark plug replacement. Upon return and repeat inspection it was discovered that oil filter was full of metal shavings and advised it was very likely necessary for a complete engine overhaul (with $18-20 K price tag). Checking online it was discovered that this GM motor had a 580,000 vehicle recall for 2021-2024 models. A new ODI study is being done for similar complaints for 2019-2021 year models (additional 280,000 vehicles). The 6.2L motors have been found to have a crankshaft/bearing issue leading to motor failure and even sudden loss of power often presenting with metal particulate matter being discovered. Awaiting resolution.

Filed Aug 27, 2025 · Brakes, Engine · OH · fire

I was driving down the highway, and my wife and I decided to stop at Costco to get protein bars and gas for the drive home. We also had a [XXX] , [XXX] old, and [XXX] in the car. As we were approaching the end of the exit ramp at approximately 30 miles per hour, the engine jerked the car two or three times then died. When it died, I lost power steering and the car slammed to a stop. The car also displayed an alert about my tow breaking system. I tried to restart it, and smoke began rising from my engine bay. I stopped trying to restart, and got my family onto the hill beside the exit while waiting for a tow. The tech at the GMC dealer stated that the engine had seized on me while driving. The cam shaft can rotate a small amount one way before getting blocked, and likewise the other way. Tech believes that the bearing is responsible, but will not be doing a tear down until September 2. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Apr 30, 2025 · Engine · WI

Vehicle suddenly lost power without warning or engine light coming on. Vehicle was inspected and found that the transmission fluid pump failing caused low transmission pressure and replacement was required. 70k transmission fluid change was done per maintenance recommendations. Vehicle had 112k miles.

Filed Mar 28, 2025 · Transmission · NC

I possess a 2020 GMC Yukon XL. During multiple highway drives, I experienced a persistent loss of power. When accelerating from a stop, the vehicle struggled to shift gears smoothly, resulting in a rough, jerking motion. I opted to take the car to the dealership; however, before I could reach it, the vehicle lost all power and failed to change gears entirely. I am fortunate this complete loss of power and ability to change gears did not occur while I was on a busy highway. I purchased the car when it had 63,000 miles, and at 120,000 miles, the dealership informed me that the transmission had completely failed. A replacement of the transmission will be necessary.

Filed Mar 23, 2023 · Transmission · VA

Transmission required replacing at 82,500 miles. Vehicle completely lost power during my morning commute. Thankfully, I had exited the Interstate and was on a city street with minimal traffic. Also thankful that I took and extended warranty at the time of purchase less than a year ago at 61,200 miles.