2021 GMC Yukon transmission problems

Filed Oct 20, 2026 · Engine, Transmission · PA

VEHICLE: 2021 GMC Yukon, 5.3L V8 (L84). VIN: [XXX]. Mileage at failure: approximately 88,000. Component: Engine. INCIDENT DATE: XXX While I was driving on a highway, the engine began to misfire and I heard a ticking noise. The check engine light then began flashing, indicating a severe misfire. I pulled off the highway immediately to a rest area. The vehicle was towed to a GMC dealer. The dealer's diagnosis suspected failed valve lifters, and the repair orders call for a misfire diagnosis with the Bank 1 cylinder head removed, and replacement of the camshaft, lifters, and related parts. This failure caused sudden loss of engine performance at highway speed. The engine began smoking. My family and I were in the vehicle, and we were fortunate there was a safe place to stop. I believe this is a known defect. GM Service Bulletin PIP5776, "Misfire Due to Collapsed Lifter," covers 2021 GMC Yukons with the 5.3L L84 engine. It describes a misfire with a bent pushrod leading to a collapsed lifter or a lifter that comes apart, and it attributes the cause to an internal lifter concern. Many other owners of GM V8 trucks and SUVs have reported the same failure, and a class action over the AFM/DFM lifters has been pending against GM in federal court in [XXX] since 2021. I bought this vehicle new and have maintained it. This is the second time this vehicle has left my family stranded on a highway. In 2024, a separate known issue left us, including three children under [XXX], on the side of a major highway about 7 hours from home. GM repaired that issue. For the current failure, GM has not agreed to cover the repair. It has offered $5,951.39 toward an engine replacement, which would leave me responsible for $13,886.59 plus teardown labor. I am filing this complaint so the federal safety agency is aware of this failure, which can cause sudden loss of power on the highway. GM case number: XXX. Dealer: Fred Beans Buick GMC, [XXX]. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

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 Oct 16, 2026 · Transmission · FL

I believe it’s a transmission. While driving down the interstate and the car just won’t get up and go like it should, and I’m gonna get rear ended. I’ve I’ve taken it to the dealership three or four times. I keep telling me nothing’s wrong.

Filed Oct 8, 2026 · Transmission · NY

I was driving normally, going up a hill and the car skipped and lurched forward. Then when i touched the gas pedal the car would not accelerate but the rpms would increase. When I was able to pull over, the car would not reverse, the engine would rev when i pushed the gas pedal but it would not move. I drove it directly to a mechanic down the road and he believes the transmission is shot and agrees that it is part of the problems that GMC is having with its transmissions, and it seems as though my car should also be included. This was an extremely dangerous and frightening thing to happen to a car with no warning whatsoever. I was lucky not to have been in an accident.

Filed Sep 15, 2026 · Transmission · 88,000 miles · DE

The contact owns a 2021 GMC Yukon. The contact stated that while driving at various speeds on several occasions, the vehicle jerked and the transmission shifted hard into 1st and 2nd gears. The message "Service Safety Restraint" was displayed. The vehicle was taken to an independent mechanic, where it was diagnosed with a failed valve body. The contact was informed that the valve body or the transmission needed to be replaced. The manufacturer was notified of the failure. The failure mileage was approximately 88,000.

Filed Sep 10, 2026 · Transmission · WI

Had a valve body failure in mid XXX. The vehicle would not go into reverse and drove it in limp mode to a dealership about 5 miles away. Fortunately they were able to get a new valve body and repair it in one day. Cost was approximately $3,500 and not covered by warranty. The vehicle had about 110,000 miles on it at the time. This is a known defect on this vehicle and a recall should be initiated. Had we started our trip from [XXX] back to [XXX] before the failure occurred, we likely would have been stranded on the highway, or worse. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Aug 29, 2026 · Engine, Fuel system · OH

Took car in to have it checked for recall on engine and have oil changed to new standards with WD40 was told the engine and car was fine “just use this new oil” A MONTH later was driving and engine would not shift come to find out our transmission was going out it was replaced thanks to our extended warranty (even tho it only had 98,000 miles on it) a week after a fuel pump was out and we had to pay to replace it. There were never check engine signs and no signs of the car having failure truly it ran great until the new oil.

Filed Jul 29, 2026 · Transmission · 78,000 miles · CA

The contact owns a 2021 GMC Yukon. The contact stated that while driving at undisclosed speeds, the transmission was shifting hard, with severe vibrations and shuddering. The vehicle was taken to the local mechanic, who confirmed the failure and advised the contact to take the vehicle to the local dealer. The vehicle was taken to the local dealer, and the failure was confirmed, but the vehicle was not repaired. The contact stated that the vehicle was previously serviced under the federal safety agency Campaign Number: 24V797000 (POWER TRAIN); however, the failure occurred. The manufacturer was notified of the failure, but no assistance was offered. The contact stated that the manufacturer had issued a special coverage associated with the failure but offered no assistance. There was no fault code retrieved associated with the previous software update that was performed under the recall campaign. The failure mileage was 78,000.

Filed Jun 26, 2026 · Transmission · VA

Transmission abruptly failed after only 110k well maintained miles

Filed Jun 25, 2026 · Engine, Fuel system · IN

Engine overheated and performed an emergency shutdown while driving through Atlanta on my way to vacation with my family. We lost propulsion and had to cross 5 lanes of traffic to find a shoulder to pull over to. The engine shut down and we were left stranded 500 miles from home with our 3 children in a boiling car. The vehicle was inspected and passed the recall test 6 weeks prior to this incident. After the first failure we attempted to extend our power train warranty to which we were told it had too many miles by GM. The GM dealership and service center where the vehicle was towed confirmed the engine needed to be replaced and GM confirmed it falls under their extended warranty. However, GM refuses to cover any additional expenses incurred from their engine failure.