2021 GMC Yukon Powertrain & Transmission Problems

Loss of power while driving on highway, would not speed up. Shaky driving. Appeared to go into limp mode. Dealer informed me that the transmission valve body will need to be replaced. No prior messages or alerts, check engine light came on after power loss.

I was pulling out of my driveway when I noticed that my mailbox was blown open from a recent storm. I stopped and put it in reverse (well tried to) but the vehicle would not shift. Quickly I continued to drive to make a u-turn instead and at that point my vehicle would not drive normally. The rpms would not go up despite pressing the gas and the engine was reving very high.gm dealer said 700 to pull the transmission to determine the issue, but after my research I’m certain it’s the valve failure in the transmission just as it’s done the same to others. Why is this transmission not recalled, but the disel engines on the same model are? Seems as though it is a similar issue. I’m afraid to see what they will charge me as my vehicle has 76,000 miles and I’m told is outside warranty coverage.

My 2021 GMC Yukon suffered the same engine failure that is the subject of the recall. It has just over 70,000 miles. I'm now told I need a new engine. The dealer confirmed that this is the same issue that has impacted other similar vintage Yukons.

On [XXX] driving to Denver the 52,000 mile yukon started making a clicking sound when accelerating on the interstate. Traction control light came on as well as the check engine light. Low power was noticed and we immediately pulled over as it sounded like it was going to blow up. Towed the vehicle 145 miles where we bought it and the shop confirmed the lifters and 5th cylinder are the issue and that the cams could be damaged. Recommend replacing each side. The car is basically new and under the 60K drive train warranty but about 100 days past the 5 year mark. Terrible timing. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

I live in Alaska. It was -13f. We were out and about and when I tried to leave and back up, the vehicle would not go into reverse. If it hadn’t been for a passing motorist my daughter and I would have been stuck there overnight, in negative temps. I was able to drive it home, in limp mode. Come to find out, it is the valve body on the transmission. That in cold temps the valve body can fail. After some research I found that it is a KNOWN issue with these vehicles and there has even been a “Urgent-Distribute Immediately” Service Update regarding the problem. Urging dealerships to review the VIN’s they have in their possession for the issue. I had the vehicle towed to a shop, where they confirmed the problem was the transmission valve body. They were unable to perform the work as it takes a qualified technician to replace. So it got towed to the closest GMC dealership. They have had it for two weeks now. They confirmed that it is a known issue and there have been no recalls. But they did tell me I was “in luck” because they stock that item so we won’t have to wait for a part. Not only is it going to cost me $3500 to replace something that is a know issue with this vehicle, but it could have ended in tragedy if no one would have come along when we were stranded. I urge you to make this a recall on these vehicles.

Clicking/rubbing noise when turning slowly. Rear differential issue diagnosed by dealer.

Electronics- module went out @40,000 brand new car Drive train teal differential went out

While my wife was driving to pickup my son from school, the vehicle was stopped at a stoplight and the engine turned off approximately 1 mile after departing the house. After getting the vehicle towed to the dealership because it wouldn’t start, it was determined by the dealership that the engine was seized. The vehicle has 60,500 miles on it and is driven by a suburban woman and has always had all maintenance done at the dealership. The vehicle is parked in our driveway and there are no signs of oil leaks or anything else that would indicate a potential engine failure. This VIN was not recalled with the larger GMC 6.2L engine failure recall, however other 2021 model years were recalled. Recommend immediate expansion of recall due to the unforeseen engine failure while driving with no previous warning lights (oil or check engine) or other indications prior to seizing. This experience indicates that the initial recall was not sufficient enough to locate and identify all of the 6.2L engines affected by the poor quality control issues at GMC.

At the time an oil change is needed, there is a warning light that says "low oil pressure and low oil." There also has been a "slipping" of the engine at around 60mph. GMC dealer states it is a torque converter. I am worried that the engine will fail or stall while driving The fuel pump control module has been replaced. Motor is not covered under the current motor recall and taking vehicle to transmission shop to have it checked as well

My vehicle is currently in repair due to a known issue with GM. GM has put out a Technical Service Bulletin 20-NA-038 referencing a "well-known" problem with Cylinder 5 failing in 2021 5.3L and 6.0L engines. However, there has not been a recall. Ironically, there were other vehicles brought to the dealership (Sam Boswell GMC in Enterprise, AL) for the same repair on the same day as my vehicle. I'm hoping to get an initiative started for a recall

the electronic solenoid in the valve body failed and it is available for inspection. it was struggling to shift on freeway at speeds of 65 mph and i would lose power. the vehicle was inspected by a gm dealership service man. there were no warning lamps when part started to fail, luckily when I parked the vehicle would not go into gear and then the warning light (check engine light) came on.

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.

Knocking coming from engine, seems like engine failure

Problems with the engine shifting gears stalling delayed or won’t engage hard shifting while it’s in motion something’s going on with the engine we’ve called several and had it serviced times of times to ask them what was going on with it in Newport Oregon you can fill it still when you drive. The problem still is not fixed. It’s been happening since we purchased it took it in right away. we’ve asked if our Vin number has come up for a recall repairs we are worried for safety and are currently parking in the car because the dealership is unable to fix what is wrong with the car. They’re telling us there is something wrong and are aware of the recall and won’t fix the problem dealership refuses to take the car they don’t want it without the recall fixed due to safety concerns. you can definitely fill it when you drive I’m not exactly sure what the other issue if with the sounds it’s making when the issue keeps happening but it’s scary There is the recall on it. They are not taking into consideration or the seriousness of the situation and the safety of lives.

For whatever reason our 2021 GMC Yukon Denali is not listed in the current 2025 GMC motor recall including cams and lifters and accompanying parts. While driving our truck about a mile from the house the vehicle began seizing and shaking (almost as if we had blown several tires); we immediately pulled over and accessed. Called Dealership and had truck towed there immediately. We are told that it needs cams and lifters and that b/c our VIN does not pull up a recall that the repairs will cost ~$9800.

A valve in the transmission is sticking causing a loss of power, engine light warnings to flash, and hard gear shifts from park to drive or reverse. First occurred on 5/25/25, went to the dealer service department on 5/26/25. Part still not available and it’s been sitting at the dealership since.

We are back on shop for lifter replacement for the 3rd timeand possibly more once they open the project. Valve springs replaced and lifters.

Valve body failure 72000 miles and warranty ended at 60000

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 (NHTSA 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.

The car is by hard shifting. The dealership found, “THE TRANS TO HAVE A SHUDDER AND DEBRIS IN THE TRANS FLUID INDICATING TORQUE CONVERTER FAILURE RECOMMEND REPLACING TRANS DUE TO TORQUE CONVERTER FAILURE SENDING DEBRIS THROUGH THE PUMP AND VALVE BODY.” The first time we brought the vehicle into the dealership they just replaced the fluid and didn’t inspect for failures. The dealership now did and if the torque converter fails the car won’t drive, if I’m on the freeway that could cause a crash or worse.