Most common 2020 GMC Sierra 3500 problems
Share of the 51 complaints; one complaint can involve more than one system. "~" is the median mileage when the problem started.
GMC Sierra 3500 complaints by model year
Best Sierra 3500 years: 2012, 2014, 2013. Years to avoid: 2024, 2020, 2023, 2025, 2022. Compare all years →
2020 GMC Sierra 3500 recalls (8)
Power train › Automatic transmission › Control module › Software
General Motors, LLC is recalling certain 2020 Chevrolet Silverado 2500, 3500, GMC Sierra 2500, 3500, and 2020-2022 Chevrolet Silverado 1500 and GMC Sierra 1500 vehicles that may have been repaired incorrectly under recall 24V797. The transmission control valve may fail and cause the rear wheels to lock up.
Remedy: Dealers will inspect the vehicles and update the transmission control software, free of charge. Owner notification letters were mailed March 6, 2026.
Power train › Automatic transmission › Fluid/lubricant › Valves/valve body
General Motors, LLC (GM) is recalling certain 2020-2022 Chevrolet Silverado 1500, 2500, 3500, GMC Sierra 1500, 2500, 3500, 2021 Cadillac Escalade, Escalade ESV, Chevrolet Tahoe, Suburban, GMC Yukon, and Yukon XL vehicles equipped with diesel engines. The transmission control valve may fail and cause the rear wheels to lock-up.
Remedy: Dealers will install new transmission control module software, free of charge. GM will provide a special coverage program to cover the repair of transmissions that are identified by the remedy software as containing a…
Latches/locks/linkages › Tailgate › Latch
General Motors, LLC (GM) is recalling certain 2020-2024 Chevrolet Silverado 2500, 3500, GMC Sierra 2500 and 3500 vehicles equipped with power-unlatching tailgates. The tailgate's electronic gate-release switch may short circuit due to water intrusion, which can result in the tailgate inadvertently unlatching while the vehicle…
Remedy: Owners are advised to check that the tailgate is closed and latched before driving. Dealers will replace the exterior touchpad switch assemblies, free of charge. Owner notification letters were mailed May 17, 2024.
Seat belts › Critical fasteners
General Motors, LLC (GM) is recalling certain 2019-2021 Chevrolet Silverado 1500 and GMC Sierra 1500, 2021 Chevrolet Suburban and Tahoe and GMC Yukon XL and 2020-2021 Chevrolet Silverado 2500 and 3500 and GMC Sierra 2500 and 3500 vehicles.
Remedy: GM will notify owners, and dealers will inspect left-side and right-side front-row center seat-belt bracket attachments and reassemble it correctly as necessary, free of charge. The recall began January 26, 2021.
Air bags › Side/window › Curtain › Inflator
General Motors, LLC. (GM) is recalling certain 2020 Buick Enclave, Cadillac XT5 and XT6, Chevrolet Blazer, Silverado 1500, 2500 and 3500 and Traverse and GMC Acadia and Sierra 1500, 2500 and 3500 vehicles.
Remedy: GM will notify owners, and dealers will replace the suspect RRAB modules, free of charge. The recall began September 3, 2020.
Latches/locks/linkages › Hood › Latch
General Motors LLC (GM) is recalling certain 2020 Chevrolet Silverado 2500 and 3500 and GMC Sierra 2500 and 3500 vehicles previously recalled under 20V-142. Some of the vehicles in 20V-324 were not part of Recall 20V-142 but received defect parts during another service (typically during collision repair).
Remedy: GM will notify owners, and dealers will replace the hood assembly, free of charge. For hoods sold over the counter, dealers will contact customers with instructions for hood replacement. The recall began July 7, 2020.
Show 2 more recalls
Latches/locks/linkages › Hood › Latch
General Motors LLC (GM) is recalling certain 2020 Chevrolet Silverado 2500 and 3500 and GMC Sierra 2500 and 3500 vehicles. The hood-latch striker wires may not have been heat-treated properly, possibly causing them to fracture.
Remedy: GM will notify owners, and dealers will replace the hood assembly, free of charge. The recall began April 13, 2020. Owners may contact Chevrolet customer service at 1-800-222-1020 or GMC customer service at…
Seat belts › Pretensioner
General Motors LLC (GM) is recalling certain 2019-2020 Chevrolet Silverado 1500 and GMC Sierra 1500, and 2020 Silverado 2500, Silverado 3500, Sierra 2500, and Sierra 3500 vehicles equipped with carpet floor covering.
Remedy: GM will notify owners, and dealers will close off the opening in the pretensioner bracket, free of charge. The recall began December 13, 2019.
NHTSA defect investigations
Federal safety investigators have looked into a possible defect involving the 2020 GMC Sierra 3500:
Air Bag Malfunction
On April 9, 2021, the Office of Defects Investigations (ODI) opened PE21-010 to investigate instances of air bag malfunction indicator light (MIL) illumination and potential for frontal air bag non-deployment in several vehicles manufactured by General Motors (GM).
What 2020 GMC Sierra 3500 owners say
Transmission & drivetrain
The contact owns a 2020 GMC Sierra 3500. The contact stated that while driving at 60 MPH, the rear differential seized, in addition, the contact was hauling a median size tracker on top of a flat bed. The flat bed jackknifed and hit the left side of the contact's vehicle. The vehicle was able to come to a stop. The air bags did not deploy. There was no warning light illuminated. A police report was filed. There were no injuries sustained. The vehicle was towed to a towing yard. The trailer was towed to the residence. The tractor was damaged in the accident. The vehicle was diagnosed by an independent mechanic. The contact was informed that the transmission had failed. The vehicle was not repaired. The insurance company was contacted. A claim was filed with the insurance company, and it was canceled a few days later by the insurance company. …
The contact owns a 2020 GMC Sierra 3500. The contact stated that after stopping at a stop light, the light turned green and the contact depressed the accelerator pedal however, the vehicle failed to accelerate as intended. The contact drove a short distance and noticed that the failure was reoccurring. The contact drove the vehicle to a safe location and turned off the vehicle. The contact exited the vehicle and noticed that the exterior of the vehicle was covered with transmission fluid. The contact stated that the transmission fluid was also on the undercarriage of the vehicle and on the ground. The vehicle was towed to the dealer where it was diagnosed with a failed transmission fluid line. The contact was informed that the transmission fluid line needed to be replaced. The vehicle was not repaired. …
Electrical system
Vehicle will not start due to known GM issues. This failure left my family stranded in cold dark unsafe area once already. If we were in the flow of traffic or had to leave an area immediately we would have been unable too. Known GM issue, engine fault code P12A6 fault code. Bulletin: PIP5719A discusses this issue. I am being told by the dealer there is a newer bulletin which advises ECM update. GM dealer is stating ECM software upgrade is required to resolve at owners expense. Owner is responsible for diagnostic fee in addition to repair costs. If the issue is not resolved vehicle may continue to experience starting failure and or other electrical problems. The night the vehicle left us stranded instrumentation was erratic and not reading properly on the instrument cluster. …
Infotainment system AND center instrument cluster went completely black - six times over the course of one month. I took the truck to Alan Webb Chevrolet in Vancouver Washington. Their service technician was aware of infotainment system "Black Screen of Death - BSD" problems due to previous repair work on several different GM models. However, on the way to their Service Department to get this fixed, I rolled down the driver's side window about 6 inches to get some fresh air and rolled it back up. Out of nowhere the Infotainment system AND the center instrument cluster came back to life. No rhyme, no reason and both stayed on (illuminated). Their Service Technician could NOT recreate the BSD. They had my truck for more than one week AND said they were working with GM engineers to resolve this issue. GM case number SR 9-7065134382. …
Brakes
driving approximately 50 mph when vehicle suddenly made loud bang and locked up rear brakes for 25' coming to a stop in road side ditch, numerous vehicles had to make evasive actions to avoid me and other vehicles. flat spotted tire abut no visible physical damage. sat on side of road for transmission temp to cool down then drove to shop without repeat. called dealer was told the earliest appt was a month away. have not been able to repeat incident so far. this has happened a few times and is becoming more frequent, mfg has tsb issued but indicates they cant assist because my warranty has expired so i will have to pay 225 per hour diagnostic fee. this is untenable and dangerous. this needs a recall and repair ASAP.
The computer lite up the dash and reduced power, plus took the trailer brakes off line. This happened while loaded. To reset the system you have to pull over and turn the vehicle off. This happens 2-3 times per day. This was a problem at 600 miles. The transmission shifted from 10 gear to 5th gear while driving 75 miles per hour. The truck had 75,000 miles on it . Had to send another truck out to pick up the load in Santa Rosa New Mexico. The dealer Glenn Polk in Sanger has been working on for the last 4 months There is never a warning until the lights come on with a system failure.
Frequently asked questions
Is the 2020 GMC Sierra 3500 a good car?
Based on 51 owner complaints filed with NHTSA, the 2020 Sierra 3500 rates avoid: 5.3× as many complaints as a typical year of the Sierra 3500 at the same age. It is one of the Sierra 3500 years we suggest avoiding. Complaint counts don't account for sales volume or individual maintenance, so have any used car inspected before buying.
What is the most common problem with the 2020 GMC Sierra 3500?
The transmission & drivetrain — 19 complaints, 37% of all complaints for this model year. Next are the electrical system (9) and brakes (7).
How many recalls does the 2020 GMC Sierra 3500 have?
There are 8 recalls for the 2020 GMC Sierra 3500, the most recent from February 12, 2026 (software). Recall repairs are free at any authorized dealer — check whether yours has been done with the VIN recall check.
What are the best and worst years of the GMC Sierra 3500?
The best years by complaints, compared at the same age, are 2012, 2014 and 2013. Years to avoid or approach with caution: 2024, 2020, 2023, 2025 and 2022. See the full GMC Sierra 3500 years comparison.
At what mileage do 2020 GMC Sierra 3500 problems happen?
The median mileage reported in complaints is about 29,000 miles; 70% of problems with a recorded mileage started before 50,000 miles.
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.