2021 GMC Sierra 3500 Reliability Data: Problems & Recalls
Caution The 2021 GMC Sierra 3500 has a complaint index of 70, ranking 7th worst out of 21 model years, and carries a Caution verdict with 20 complaints and 5 recalls. Transmission & powertrain issues lead reported problems at 35% of complaints, with a median failure mileage of 133,000.
Based on NHTSA complaints per model-year, not a reliability rating. Methodology
YearToAvoid Scorecard
- Complaint Index
- 70/100
- #7 of 21 Sierra 3500 years
- Verdict
- Caution
- vs. other years of this model
- Complaints
- 20
- unique NHTSA reports
- Recalls
- 5
- 1 Park Outside
- Crashes
- 0
- reported in complaints
- Fires
- 0
- Injuries
- 0
- Top issue
- Transmission & Powertrain
Top 2021 GMC Sierra 3500 problems
Share of this year’s NHTSA complaints by component group. Groups with 15+ complaints have their own page.
- Transmission & Powertrain7 (35%)
- Brakes5 (25%)
- Electrical System4 (20%)
- Engine3 (15%)
- Other3 (15%)
- Fuel System2 (10%)
- Collision Avoidance & Cameras1 (5%)
- HVAC1 (5%)
- Structure & Body1 (5%)
- Suspension, Wheels & Tires1 (5%)
A complaint can list more than one component, so shares add up to more than 100%. Shares are % of complaints.
What owners report
- Transmission unexpectedly downshifts to a low gear at highway speed while towing, causing sudden and dangerous deceleration.
- Owners report the transmission struggles to hold higher gears uphill and the rear wheels lock up, limiting the truck to very low speeds.
- Brake pedal feels extremely soft and requires being pressed to the floor to stop the vehicle, even after dealer inspection.
- Trailer brake wiring intermittently disconnects, cutting brake power for extended periods while towing.
- Diesel exhaust fluid heater failures trigger warning lights and limit the truck's speed to a crawl.
- Electronic key fob in a pocket can inadvertently lock or unlock the vehicle due to button placement.
2021 GMC Sierra 3500 recalls
5 NHTSA recall campaigns list this model year.
- NHTSA 24V797000Oct 24, 2024Transmission & Powertrain463,295 vehicles
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.
Risk: Rear wheel lock-up can increase the risk of a crash.
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 defective control valve. Owner notification letters were mailed December 12, 2024. Owners may contact GM customer service at 1-888-988-7267, Cadillac customer service at 1-800-458-8006, GMC customer service at GMC 1-800-462-8782 or Chevrolet customer service at 1-800-222-1020. GM's number for this recall is N242454440.
- NHTSA 24V060000Feb 1, 2024Structure & Body570,434 vehicles
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 is in park.
Risk: An unlatched tailgate may open while driving and result in a loss of unsecured cargo, creating a road hazard and increasing the risk of a crash.
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. Owners may contact Chevrolet customer service at 1-800-222-1020 or GMC customer service at 1-800-462-8782. GM's number for this recall is N232426400.
- NHTSA 21V758000Sep 29, 2021Brakes3,241 vehiclesPark Outside
Service brakes, hydraulic:power assist:electric:control module
General Motors, LLC (GM) is recalling certain 2021-2022 Chevrolet Silverado 2500, Silverado 3500, GMC Sierra 2500, and Sierra 3500 vehicles with electronic brake control modules (EBCM) replaced during vehicle assembly. The bolts that attach the brake pressure modulator valve (BPMV) assembly may not be properly tightened, which could fail to seal the two sub-assemblies and allow water intrusion.
Risk: Water in the BPMV may cause an electrical short circuit and increase the risk of fire.
Remedy: Owners are advised to park outside and away from other structures until the recall repair is completed. Dealers will replace the BPMV assembly, free of charge. Owner notification letters were mailed on October 20, 2021. Owners may contact Chevrolet customer service at 1-800-222-1020 or GMC customer service at 1-800-462-8782. GM's number for this recall is N212349181.
2021 compared with other Sierra 3500 years
Frequently asked questions
- Is the 2021 GMC Sierra 3500 reliable?
- It has a complaint index of 70 and ranks 7th worst among 21 model years of the Sierra 3500, earning a Caution verdict. Transmission and brake issues make up 60% of reported problems.
- What are the most common problems on the 2021 GMC Sierra 3500?
- NHTSA complaints show Transmission & Powertrain issues account for 35% of complaints, followed by Brakes at 25% and Electrical System at 20%.
- Does the 2021 GMC Sierra 3500 have any recalls?
- NHTSA lists 5 recalls for the 2021 Sierra 3500, covering transmission control module software, tailgate electronics, brake control modules, and seat belt bolts and brackets.
- At what mileage do transmission problems tend to appear?
- The median mileage at failure across all reported problem areas for this year is 101,500 miles, with the Transmission & Powertrain category showing a median of 133,000 miles.
- How does the 2021 Sierra 3500 compare to other model years?
- With a complaint index of 70, the 2021 model ranks worse than most other Sierra 3500 years, though not as high as 2024 (100) or 2020 (95), both rated Avoid.