2021 GMC SIERRA 1500 Complaints

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

When my android auto does not connect, it essentially disables the whole infotainment system which is incredibly distracting and dangerous while driving. I am requesting that this be fixed so that I can still use some of the infotainment system but they are redusing to to do anything to fix the issue. The dealer has advised that they are unable to fix the issue because it is software related but yet the software team is saying it is a dealer issue. Please help me get a resolution to this issue!

The contact owns a 2021 GMC Sierra 1500. The contact stated that on Aug. 14, 2025, the PICO engine test was completed on the vehicle under NHTSA Campaign Number: 25V274000 (Engine and Engine Cooling). The dealer stated that the engine had passed the test, and the engine oil was changed to a higher viscosity oil, and the oil cap, oil filter, and the page in the Owner’s Manual were updated. The contact stated that the vehicle was making abnormal sounds while idling, and the fuel consumption had increased. The dealer was contacted and advised the contact to bring the vehicle back to have the engine test performed again; however, the contact refused. The vehicle was not repaired. The contact stated that the engine test had not been performed on the vehicle and that the vehicle was unsafe. The manufacturer was informed of the failure and informed the contact that the vehicle was repaired. The failure mileage was approximately 44,000.

at roughly 5,000 miles had lifter failure which caused loss of power. That was repaired under warranty. Same issue at 86,000 miles - loss of power. New engine which I had to pay for. Same issue at 126,000 miles. New engine required. Covered under warranty. Side note. New engine will only have balance of warranty from 2nd engine or about 5,000-6,000 miles. first incident Feb 2001, second incident about Nov 2004, third incident Mar 2026.

Loss of power, and knocking from the engine while driving. Check brake system, check srs, check parking brake and check engine light flashing came on at the same time. The problem has been reproduced at a mechanics shop and has been determined that cylinder 6 is dead.

Following the remedy of the engine recall in 2025, the truck started having intermittent electrical issues (i.e. warning lights on dash turn on/off: service 4WD, Loss traction Control, etc) come one while the truck is being driven. If the truck is turned off while the dash warning lights are on, it will NOT Start for about 24 hours. If the warning lights are ignored, eventually they will go off on their own. Additionally, the truck is having "no-start" problems (randomly the truck does not start, then after a few days it starts). A New development, when backing up there is a scraping/squealing sound (possibly universal joint). Truck has been back to the dealership that replaced the engine block for the recall and they have failed to identify any issues as these problems are intermittent. Engine Recall Replacement Invoice (Attached)

Took it to dealer for engine sound said nothing was wrong 4 days later rod bearing went out while driving. Truck no longer able to drive

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.

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.

[XXX] we bought our 2021GMC Sierra 1500 from Dealer with 39842 on it. we drove the truck 2910 miles when we checked the oil it was 2 quarts low at 42752. we added oil at that time and called our local dealer to make appointment . appointment at Bowser route 51 Pleasant Hills PA 15236 They informed us they would have to charge us for an oil change to start an oil consumption test on 10/23/25 miles 43829. 11/24/25 brought back to Dealer they said the oil was full yet i checked it in morning it was1/4 low. 1/7/26 brought back to dealer this time they let our truck sit over night the best way to check it and found it to be 3/4 low with only 1,698 miles driven also the antifreeze reservoir was low also they topped off both. 3/8/26 I Checked it ,its now 1 quart low with 1,097 miles driven milage on truck now is 46,623. Summarize GMC will not even look into why my truck is using oil not once my truck is still under warranty where is the consumer protection. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)