GMC Sierra Complaints (2020)

626 consumer complaints on file.

#11774319October 28, 2026
ENGINE
6.2 liter engine failed at 59,300 miles. Being replaced right now with remanufactured engine. 2020 GMC Sierra is not part of recall but others have had problems as well
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11774106October 27, 2026
SERVICE BRAKES, HYDRAULIC
The contact owns a 2020 GMC Sierra 2500. The contact stated that while driving 65 MPH, there was a burning odor coming from the vehicle. The contact depressed the brake pedal, however, the vehicle failed to respond as needed. The vehicle was pulled over to the side of the road, coasted into a ditch, and went into a field before coming to a stop. After the vehicle came to a stop, the contact became aware that there was a fire behind every wheel, and the flames had spread to the grass. The fire was self-extinguished. The contact referenced NHTSA Campaign Number: 21V758000 (Service Brakes, Hydraulic); as the possible cause of the failure; however, the VIN was not included in the recall. The contact stated that the failure had previously occurred in 2023. The vehicle was towed to a tow yard. The failure mileage was 201,000.
Crash:
No
Fire:
Yes
Injuries:
0
Deaths:
0
#11773206October 23, 2026
STEERING, ENGINE
This morning it seems as if my 6.2L GM motor threw a rod. All the initial sounds and check engine information point toward that. I will be taking it to a dealer to confirm the issue. Data center driving ability and sounds indicate steering was affected as well or is somehow connected.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11773333October 23, 2026
POWER TRAIN, ENGINE
I own a 2020 GMC sierra AT4. It has developed a shudder when cruising on the highway or driving in town around 1500rpm. I believe it is coming from the transmission. A local shop mentioned the torque converter. The shudder feels like a delay in power and makes it difficult to hold speed or accelerate when needed.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11772753October 21, 2026
UNKNOWN OR OTHER
Transmission control valve real,rear wheels can lock up causing accident recall # 26V083000
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11772065October 19, 2026
ENGINE
I was driving and my truck shut down on me while I was driving down the road, I had to get it towed to the dealership where it was confirmed that the motor would need to be replaced. There was no warning, it just turned off and luckily I was able to coast to a safe area to wait for the tow truck.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11771820October 17, 2026
ENGINE, FUEL/PROPULSION SYSTEM, POWER TRAIN
[XXX] General Motors Company P.O. Box 33170 Detroit, MI 48232-5170 c/o Franklin, Customer Support Re: Formal Demand for Buyback – 2020 GMC Sierra AT4 Black Widow VIN: [XXX] | 6.2L Engine Recall ~ 25V-274. Plus ~ GM 10-Speed Transmission, Multiple Recalls Dear GMC Legal, I am providing written notice as required by 15 U.S.C. §2310 and New York State Lemon Law. This vehicle substantially impairs the safety, use, and value of my truck, and I am requesting a full buyback. The Facts: On [XXX], the vehicle was taken out of service and remained at the shop for 11 weeks. It was returned with yellow marking paint splattered on the exterior, floor mats, and brake pedal. On [XXX] — with fewer than 400 miles on the replacement engine — the engine and/or transmission suddenly shut off at 55 mph on [XXX]. It restarted with a violent boom, then cycled between shutting off and restarting with loud clacking and shaking for the remainder of the drive. I was forced to drive at 25 mph with hazard lights to reach home. The Legal Basis: This is a safety defect on a vehicle subject to Recall 25V-274. GM was on notice of this known, concealed defect. The vehicle has been out of service for 30+ cumulative days. I have been denied a reasonable opportunity to cure. The vehicle has caused me severe and ongoing psychological distress, imminent and uncontrolled danger to my life, and total and continuing loss of use for its fundamental purpose. My Demand: 1.Full buyback under New York State Lemon Law — full purchase price, loan payoff, taxes, registration, and all incidental and consequential damages. 2.$5,000 additional compensation for the safety hazard and loss of use. 3.Attorney's fees and costs under 15 U.S.C. §2310(d)(2). I reserve all rights under the Magnuson-Moss Warranty Act, New York State Lemon Law, and all applicable consumer protection statutes. Please respond in writing within 10 business days. If unresolved, I will join the c INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11771423October 15, 2026
UNKNOWN OR OTHER
Rear sliding window leak. Water stains on head liner unsure of addition damage.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11771297October 15, 2026
ENGINE
Driving down road started to hear a weird growling knocking sound and noticed a reduction of power. also noticed lower then normal oil pressure. Changed oil found metal shavings in the oil. sent to chevy dealership. Diagnosed "rod bearing failure" needs new engine.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11771040October 14, 2026
VISIBILITY
The contact owns a 2020 GMC Sierra 1500. The contact noticed an abnormal odor inside the vehicle. Upon inspection, the contact observed that the roof, rear seats, and rear carpet were saturated with water. The vehicle was taken to the dealer, where the contact was informed that the rear sliding window frame connected to the roof was fractured, causing water to leak into the vehicle. The contact was informed that the failure was a factory defect associated with an unknown recall; however, the VIN was not included. The manufacturer was notified of the failure by phone and referred the contact to the dealer. The contact was advised that the repair was not covered because the VIN was not included in the recall. The failure mileage was approximately 90,320.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11770786October 13, 2026
ENGINE AND ENGINE COOLING
The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the vehicle suddenly entered Limp mode without warning. The vehicle was taken to the dealer, where the computer was reflashed and the vehicle temporarily returned to normal operation; however, the failure recurred and the vehicle was returned to the dealer. The contact noticed a burnt odor coming from the engine compartment, along with engine bay cooling fans running at an unusual rate. Upon further inspection, the dealer diagnosed the failure as a defective coolant valve. The contact associated the failure with GM Special Coverage TSB N252508341; however, the VIN was not included in the coverage program. The manufacturer was notified of the failure. The failure mileage was 107,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11770894October 13, 2026
POWER TRAIN
The contact owns a 2020 GMC Sierra 2500. The contact stated that while stopped at a traffic light and making a left turn at approximately 20 MPH, the transmission failed. The vehicle was unable to exceed 10 MPH. The check engine warning light illuminated, and a dinging sound was heard following the incident. The vehicle shifted erratically, jumped gears, and made unusual noises. The contact associated the failure with NHTSA Campaign Number: 24V797000 (Power Train). The vehicle was towed to the dealer for diagnosis. The dealer confirmed an internal transmission failure and clutch lockup, with DTC P2732. Additionally, the transmission fluid was burnt and contained metal shavings. The dealer contacted General Motors after informing the contact of the repair costs. The failure mileage was approximately 107,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11769874October 8, 2026
ENGINE
I have a 2020 GMC Sierra 1500 AT4 with the L87 6.2L V8. The cam shaft and lifters have failed for a 2nd time. The first time happened in 2022. It was under warranty and happened at approximately 40,000 miles. This last time it happened in 2026 and was at 125,000 miles - both for the same thing - cam shaft and lifters. Both were sudden failures and luckily I was on a highway that wasn't buy at the time. This time it is costing me $10,000 to fix. They have had the truck for two months now. My understanding is the significant recall that occurred was being investigated to see if it should be expanded. I believe it should have been expanded. Whatever came of that decision? GM told me they could offer no help as my truck was out of warranty and my truck was not on the recall list. I'm curious if it will be expanded and what would happen in my situation if it is expanded. GM has deleted the support message chain that went on for four weeks where I was trying to get them to cover it under the recall and/or explaining the entire situation. Thanks, [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11769499October 7, 2026
ENGINE
While driving down interstate noticed drop in oil pressure and immediately a noise in engine with loss of power. immediately took it to dealership and they diagnosed rod bearing failure. Gm refuses to pay for engine.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11769576October 7, 2026
ELECTRICAL SYSTEM
The contact owns a 2020 GMC Sierra 1500. The contact stated that the vehicle failed to start intermittently and needed to be jumpstarted. The vehicle was taken to the dealer, and it was determined that there was corrosion on the ground wire which caused the failure. The vehicle was not repaired because the vehicle was not included in Customer Satisfaction Program: N252515590 with NHTSA ID Number: 11027795 (Electrical System) for the ground wire replacement. The manufacturer was informed of the failure and confirmed that the vehicle was not covered. The manufacturer referred the contact to the NHTSA Hotline to report the failure. The failure mileage was approximately 51,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11769733October 7, 2026
STRUCTURE:BODY
My rear spoiler roof area leaks. This is something GM knows about and has sent out memos to dealers. To fix this it’s around $1000. I think GM should fix a problem they have been well aware of for sometime.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11768916October 5, 2026
ENGINE
My 2020 GMC Sierra 1500 SLT with the 6.2L L87 engine experienced complete engine failure at approximately 129,000 miles. The vehicle is currently at Trent Cadillac GMC in New Bern, NC and is available for inspection upon request. The dealer confirmed the engine requires replacement along with timing-chain-related repairs, estimated at approximately $11,000. Before the failure, I had previously reported concerns involving oil pressure/engine operation to a Chevrolet dealer. At one visit, the dealer documented that it could not duplicate the oil-pressure concern. The vehicle was later serviced again, but the problem ultimately progressed to complete engine failure. When the truck arrived at Trent after the failure, no oil registered on the dipstick. This presents a safety concern because sudden engine failure and loss of power can leave a driver unable to maintain normal vehicle operation or safely exit traffic, particularly at highway speeds. After the failure, the truck was evaluated by Big Boys in Grimesland, NC and then towed to Trent Cadillac GMC for authorized GM dealer diagnosis. GM Customer Care has also reviewed my case. I am concerned this failure may be related to known failure patterns involving GM 6.2L L87 engines and internal engine components. Although my 2020 model is outside the current recall population, it experienced complete engine failure after earlier oil-pressure concerns. I am requesting this failure be documented and evaluated as a potential safety defect, including whether earlier-model L87 engines may experience similar failure mechanisms.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11769058October 5, 2026
LATCHES/LOCKS/LINKAGES:TAILGATE:LATCH
The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving 45 MPH, the tailgate opened unexpectedly after inclement weather or after the vehicle was washed. There was water and rust found inside the tailgate release button, and the message "Tailgate Open" was displayed. The contact associated the failure with Customer Satisfaction Program: N232426401. The manufacturer was notified of the failure. The failure mileage was 29,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11768586October 2, 2026
ENGINE AND ENGINE COOLING, ENGINE
The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving 74 MPH, the vehicle made a loud banging sound, reduced engine power, and was losing oil pressure. The dealer associated the failure with NHTSA Action Number: EA25007 (Engine, Engine and Engine Cooling). The dealer was contacted and the vehicle was diagnosed with rod bearing failure. The manufacturer was contacted by phone and made aware of the failure. The failure mileage was approximately 124,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11768156September 30, 2026
ENGINE
The engine blew up driving down the road 5k miles past warranty. Complete junk and had to pay for a new one. They would only put in another defective 6.2 gmc engine and it will fail again
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0

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