132 of the 741 complaints about the 2021 GMC Sierra 1500 are about the transmission — 18% of everything reported for this model year. Half of the failures with a mileage on record happened before 66,780 miles.
132
Complaints
0
Crashes
0
Fires
0
Injuries
Filed with NHTSA, in their own words.
POWER TRAIN
Transmission Valve Body failure. - Caused wheels to lockup momentarily and killed the engine with sudden loss of propulsion. Link to video of incident: [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
NHTSA complaint #11756447 — an unverified report by a vehicle owner.
POWER TRAIN
The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the transmission was shuddering, especially while driving uphill. The dealer was contacted, and the vehicle was diagnosed and determined to have a failure associated with a GM TSB for the incorrect transmission fluid inside the transmission reservoir. The vehicle was not yet repaired. The manufacturer was not made aware of the failure. The failure mileage was approximately 38,875.
NHTSA complaint #11754985 — an unverified report by a vehicle owner.
POWER TRAIN
2021 Harley Davidson Sierra 4WD, 6.2L L87. Started the truck in the morning and immediately heard intermittent, very loud banging noise coming from engine. Shut truck down quickly and had it towed to dealer. Diagnosis was bent pushrods & failed lifters which were replaced under warranty. Factory warranty expired only 4 months after this failure, and the recall does not include my VIN so I did not get an extended warranty or any other protection. GM has yet to even reimburse the tow bill. Completely unacceptable for a truck that was well over $100k when new.
NHTSA complaint #11753693 — an unverified report by a vehicle owner.
POWER TRAIN
On June 25, 2026, at approximately 84,000 miles, while traveling approximately 60-65 mph on Highway 121 in a posted 65 mph zone, driving my 2021 GMC Sierra 1500 AT4 equipped with the 6.2L L87 engine, multiple warning messages suddenly appeared, including “Check ESC,” “Check Parking Brake,” “Check Brakes,” and “Check Engine.” The engine began operating abnormally. I drove directly to Sewell GMC because I was concerned that the engine could fail or the vehicle could lose propulsion while in traffic. There was no crash, fire, or injury. Sewell GMC inspected the vehicle and confirmed catastrophic internal engine damage. The technician found metal debris in the engine oil and oil pan, damaged internal bearings, and camshaft/lifter damage. Sewell advised that the complete engine must be replaced. The vehicle remains at the dealership, has not yet been repaired, and the engine and failed components should be available for inspection. Before this incident, I had not experienced warning lights or symptoms indicating that an imminent catastrophic engine failure would occur. GM and the dealership advised that my VIN is not included in the current L87 engine recall because the engine was built in 2020. However, the diagnosed bearing damage, metal contamination, and catastrophic engine failure appear similar to the engine failures addressed by that recall. I am reporting this because an unexpected internal engine failure while driving creates a serious risk of loss of propulsion and a collision.
NHTSA complaint #11752087 — an unverified report by a vehicle owner.
POWER TRAIN
The 10 speed automatic transmission shakes and jumps between gears. The transmission also shakes and rumbles at cruising speeds. The diesel engine version of this truck is already recalled. My truck is a gas engine and should also be recalled. This is the same defective 10 speed transmission used in all GM vehicles and recalled in many. This vehicle needs to be recalled and fix before the wheels lock up and kill someone.
NHTSA complaint #11750566 — an unverified report by a vehicle owner.
POWER TRAIN
transmission shuddering, harsh or delayed shifting, and erratic gear changes. The truck jerks really bad during each shift of the ten speeds. A vibration or shudder typically occurring at speeds between 25-65 mph under light throttle. Also makes a bad noise every times it’s shifting. I have no lights on the dash and the gmc app tells me everything is fine when clearly it’s not . I see there’s a recall for my year and make but for some reason my vin doesn’t fall in the category
NHTSA complaint #11749233 — an unverified report by a vehicle owner.
POWER TRAIN
My car suffered a catastrophic engine failure, metal schards were found in the oil filter and was left out of the 2021 recall 25V274. The in service date of vehicle is March 13, 2021. The car was 83 days out of warranty when the engine failed. The truck has 47,000 miles on it. They are now trying to charge us, barter with us. They have gone from $2800 for repair, negotiated down to $100 to sign this off as a good will repair stripping us of lemon law rights and future recall remedies. Car is currently sitting at the dealership.
NHTSA complaint #11749076 — an unverified report by a vehicle owner.
POWER TRAIN
Dashboard lit up with engine light and stated that there's no compulsion
NHTSA complaint #11748647 — an unverified report by a vehicle owner.
POWER TRAIN
The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the brake pedal was depressed, but the vehicle continued to move forward. There was no warning light illuminated. The vehicle was taken to the dealer and was diagnosed with transmission failure. The contact stated that the valve body and torque converter needed to be replaced. The dealer informed the contact that the transmission might need to be replaced. The vehicle was not repaired. The manufacturer was not made aware of the failure. The failure mileage was approximately 65,561. The VIN was unavailable.
NHTSA complaint #11745943 — an unverified report by a vehicle owner.
POWER TRAIN
While driving my vehicle, the engine and transmission lost power and the check engine light came on. The vehicle went into limp mode and engine propulsion was limited. Had I been traveling at a faster speed, this would have been very unsafe. After coming to a stop, placing the transmission in reverse did not move the vehicle and there was a grinding noise. I was able to savely move forward in limp mode, but the shifting was harsh. I was able to find an empty parking lot to safely park. The truck was towed to Jim Winter dealership in Jackson MI for inspection.
NHTSA complaint #11744736 — an unverified report by a vehicle owner.
POWER TRAIN
When pressing on the gas, especially when moderately accelerating, the truck experiences severe shaking, which interferes with acceleration, as well as causing the truck to "jump" when the transmission gear "catches", even while driving. When the truck is at a full stop and the engine is auto off, when it restarts, it does so frequently when it reengages that it causes a physical "jump" in the vehicle, causing the driver's foot to come off the brake pedal. This has been most noticeable since my vehicle hit about 70k miles. I currently have 84k miles. I engaged the dealer and was told the transmission is out of warranty. I see that other GMC Sierra models suffer similar problems and recalls have been issued to GMC that they must repair those vehicles. Despite that, my vehicle is not included in any current recall program.
NHTSA complaint #11744554 — an unverified report by a vehicle owner.
POWER TRAIN
So I made an appointment to have my truck recalled and the Wednesday before I took it, and it cranked no start and I called the dealership. Ask if they had any other those like this and they said that it could be the fuel injector module and so I got it to a mechanic shop to read the codes and it gave me a code p062b and I asked the dealership to look into it and they never figured out what we were not wrong. I just testing the battery. Well, then I got it back after the recall was done and new transmission valve body put in and about 30 miles down the road it started to shake violently and had a flashing engine light so I got it home called the dealership the next morning because they were closed set up another appointment got it to the dealership dealership said it had a couple misfires but since it wasn’t over 100 they weren’t concerned even though I’m pretty sure it is related to the fuel model going out because it has been cranking rapidly whenever I try to start it, but they won’t do anything to figure out what’s wrong?
NHTSA complaint #11744628 — an unverified report by a vehicle owner.
POWER TRAIN
While coasting down or under very light acceleration between 12-20 mph the vehicle has a shudder like driving over a highway rumble strip. While cruising on the highway at 65+ mph, the vehicle has a light shudder or vibration. Vehicle has been checked numerous times for wheel and tire inconsistencies. Brake pads and rotors have also been replaced with no change in issue. Headlights daytime running light changes color from bright white to purple during warm weather. The vehicle has been to 3 different GM dealerships and they acknowledge the issues but do not provide a resolve.
NHTSA complaint #11743882 — an unverified report by a vehicle owner.
POWER TRAIN
power steering locked up while driving. multiple dash lights turned on, on its own after the issue, 4wd, emergency brake, abs, and other ones im not sure what they are. took it to the dealership for a recall and told them the issue that happened.
NHTSA complaint #11741189 — an unverified report by a vehicle owner.
POWER TRAIN
power steering locked up while driving. has been inspected and repaired by manufacturer. recall.
NHTSA complaint #11741190 — an unverified report by a vehicle owner.
POWER TRAIN
The truck randomly will not detect that it was shifted into park. Shifting between gears and back to park does not automatically fix the the issue and has taken up to 10 mins to turn the truck off. The adaptive cruise controls stopped working and can still use regular cruise control. Just not adaptive. It appears greyed out. The truck has thrown the error code: P1098, Engine Coolant Control Valve Position Sensor Minimum Stop Performance. The truck would go into limp mode until the error was cleared. This error has appeared 4 times over the past five months. The most recent date of it happening was today. 06/30/2026
NHTSA complaint #11741078 — an unverified report by a vehicle owner.
POWER TRAIN
The truck has a studder that comes from the transmission when at highway speeds. the studder can be felt at random intervals (seconds) from all passengers. The studder is also present on starting up a slope or accelerating from a stop at a slow pace. when accelerating slowly the jerk is more prominent. We have taken it to the GM Dealership, they confirmed the issue was present. The dealership said the GM guidence was to 1st try a re-program and then replace the torque converter. The program flash was unsuccessful, then we paid $4000 to change the torque converter. The Tech stated that this was the GM suggested fix, but noted that we are changing the fluid also which could mask the issue if it is the valve body causing an issue. The replacement torque converter and fluid did somewhat reduce the issue for a short period of about 2 months before it has returned as it did before. The next option from the dealership is in excess of $8,000 for a remanufactured transmission which is outside our reasonable spend, when we dont expect the remanufactured transmission will have any better valve body components. The recent recall did not cover my gas 6.2L sierra 1500, although it clearly is insufficient stating that it just a warning that there is a safety risk present. The valve body of the transmission appears to be an issue across all models and the recall addresses that it is present. We continue to drive this as the primary family vehicle with the hesitation and jerking present as GM dealer offered no support other than $8,000 remanufactured transmission on top of the $4000 we already spent. I believe the recall was insufficent in covering the Gas models with the exact same transmission and known issue. I also believe the offered solution continues to put those driving at risk.
NHTSA complaint #11740118 — an unverified report by a vehicle owner.
POWER TRAIN
Right after i bought the car I had a very bad misfire on cylinder 1, the car would shake at idle. Took to dealership and they said they replaced all the spark plugs and replaced cylinder 1 coil. about a week later the misfire and shaking started again but this time it would come and go. the check engine light would be on then it would go away for a bit and then come back on over and over again. The only thing that seemed to work is if i disabled the stop and go start system and put the car in L9 to disable the AFM. This seems to work and I have since bought a disabler for these systems. However, there is still a vibration at idle and i feel that its a temporary fix to a bigger issue. This is my daily driver and constantly have my children in the car and just want the car to be safe for everyone. The transmission downshifts rough and at times seems to slip/lock up while driving. I haven't brought it to the dealership for this as of yet.
NHTSA complaint #11737211 — an unverified report by a vehicle owner.
POWER TRAIN
Coolant control valve has failed and caused the check engine light to occur is available for inspection. Could cause the car to overheat and cause harm to myself or others Yes has been confirmed by dealer No GM has a special coverage out for the specific vehicle and model years for this vehicle, but are stating that my vehicle does not pertain to that coverage.
NHTSA complaint #11735894 — an unverified report by a vehicle owner.
POWER TRAIN
While driving into work, I noticed a knocking sound from the outside of the vehicle. Once parked, upon further inspection I narrowed down the area of the noise to the bottom rear of the engine/front of transmission. Fortunately, I was able to park in front of my office building and wasn’t stranded on the side of the road but under different circumstances it could've been the side of a busy highway or hours from home. I had the vehicle towed to the dealership I originally purchased from, the dealership was able to duplicate the issue with me present. Later that afternoon I was informed that the engine had failed and a replacement would be ordered. There was no prior indication of a problem or warning/CEL’s. The engine failed after the dealership had completed the engine recall ( pico test and 0-40W oil change ) related to the vehicle. I am reporting this in hopes that it helps with the investigation. This has been very disappointing for me as I have supported the brand of vehicle for many years. Only to have many issues under 80,000 miles and to lose confidence in the vehicle I purchased and the company.
NHTSA complaint #11731720 — an unverified report by a vehicle owner.
POWER TRAIN
The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving approximately 45 MPH, the transmission inadvertently shifted from drive (D) to first gear. The check engine warning light was illuminated. The vehicle was pulled over to the side of the road and then towed to the dealer, where it was diagnosed, and it was determined that the valve body needed to be replaced. The vehicle was not repaired because parts were not available. The manufacturer was notified of the failure. The failure mileage was approximately 103,000.
NHTSA complaint #11730861 — an unverified report by a vehicle owner.
POWER TRAIN
I have a 2021 GMC Sierra 1500 AT4 3.0L diesel pickup truck with 98,500 miles. The coolant control valve failed on my vehicle and for some reason it is not covered under GM's special bulletin that covers this part 15yr/150,000. Ridiculous.
NHTSA complaint #11729967 — an unverified report by a vehicle owner.
POWER TRAIN
I believe the torque converter is failing. While driving approximately 38 mph and also 48 mph up to 51 mph the vehicle have a vibration feeling like driving on a rumble strip. If you maintain the same speed, the vibration continues if you speed up, slow down, or let off the gas it goes away. There are so many detailed explanations on forums and social media from other customers experiencing the same problem, but not seeing any recall made by GMC.
NHTSA complaint #11728402 — an unverified report by a vehicle owner.
POWER TRAIN
I've been to the dealership a few times due to the truck jerking violently under very light acceleration when its trying to shift gears. also there was a few times that the rear wheels have locked up while driving.
NHTSA complaint #11726248 — an unverified report by a vehicle owner.
POWER TRAIN
The DEF tank in my truck is defective and its the second time in the last 14 months it has broke. The part is now back ordered and according to the dealership this is a nationwide issue regarding these specific trucks. I have contacted around 10 dealers in my area and all tell me the same thing that they have multiple trucks waiting on the same issue. I have not had my truck for over 2 months and have no idea when i will be getting it back due to dealership having no idea when the part will be released due to the back order. This seems to a huge issue with these trucks and GM is doing nothing to help resolve it. I've reached out to GM directly and get no assistance and now have made 2 payments on my truck and the dealership refuses to give me a loaner vehicle. i am looking for some help or relief on what to do to go about my issue
NHTSA complaint #11725796 — an unverified report by a vehicle owner.
POWER TRAIN
Driving down the road and engine shut off and would not start back. Had it towed to dealer and it needed a motor replacement. Waited over a month for the shop to finish it. New motor has 3k miles on it and is making noise, transmission is stuttering hard and the air conditioning quit working all around the same time. Had to take the truck back to the dealer after the replacement motor was installed because of a faulty “new” starter.
NHTSA complaint #11722817 — an unverified report by a vehicle owner.
POWER TRAIN
Transmission Shuttering which was confirmed from from GMC dealership , but refused to do any repairs after confirmation or diagnostic and test driving. Demanded a 220$ fee be paid before releasing my vehicle back. Also gave GMC Bulliten # 25-NA-148 which states the same issues I'm currently having.
NHTSA complaint #11722823 — an unverified report by a vehicle owner.
POWER TRAIN
The valve body failed, brought it in to a GMC dealership 3 months ago they told me the valve body is on back order. Last week they received the new valve body installed it and tried to program it. While programming it, the brand new valve body failed. So now I am stuck again with no ETA of when a new valve body will be sent to the dealership to fix the issue. this is obviously an issue with the make and model and in my opinion should be a recall. I do not feel safe if I ever get my truck back from this issue due to ongoing valve body failures nation wide and two on my end.
NHTSA complaint #11722468 — an unverified report by a vehicle owner.
POWER TRAIN
With the cruise set at 55-60 mph the Rpms will jump, along with a slight shudder feeling. Cruise control has turned off a few times due to this. Cruise set at 25mph and would shudder/lunge forward. Torque converter is showing it’s slipping and will need replaced. No check engine lights.
NHTSA complaint #11722047 — an unverified report by a vehicle owner.
POWER TRAIN
Per GMC dealership, this vehicle suffered a Transmission valve body failure and they are recommending replacement of the entire transmission.
NHTSA complaint #11721466 — an unverified report by a vehicle owner.