2021 GMC Sierra 1500: engine and transmission complaints
VERY HIGH COMPLAINT SIGNAL
77%
427 of 560 relevant owner complaints are about the engine, transmission or fuel system
77% of relevant owner complaints filed with NHTSA on the 2021 GMC Sierra 1500 are about the engine, transmission or fuel system. Well over half of everything owners reported is the drivetrain. That is a severe model-level pattern; every model year we track at this level has a documented failure behind it.
Worse than 97% of the 1,230 model years we track (2010–2023).
Looking at a specific Sierra 1500?Check its VIN: the full report, quotes about its own engine, and whether its recalls are still open. First report free.
The percentage is each model year's drivetrain complaint share. No elevated signal describes the model year, not any one car; a well-kept example of a flagged model can still be the right buy, and any of these still needs an inspection.
What owners reported
ENGINE09/10/2026
Engine stop working, lots of black smokes through the exhausts and vibrating weird. Lifters failed amoung other parts and they deemed the engine bad so they replaced it with a new one. The new engine started to make the same weird noises.
ENGINE09/09/2026
Coolant Control Valve failure. This vehicle year is included in a GM bulletin that extends the Coolant Control Valve replacement coverage to 150K miles due to a faulty design. My is valve failing exactly as described in the bulletin and GM will not cover the replacement due to my vin number. The vehicle randomly goes i…
STEERING,SERVICE BRAKES,ENGINE09/09/2026
XXX 2021 GMC Seria 108,339 miles driving home from [XXX] in town and out of nowhere the lights on the dash light up I saw it say adaptive steering and something breaking. There was a lot going on as the steering was rapidly shaking limited breaking while trying to avoid a collision. The engine started a loud knocking s…
Three of 427 drivetrain complaints. The full report shows more, with quotes about the engine in the car you are looking at first.
Recall campaigns on this model year (7)
SEAT BELTS
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 Che…
SEAT BELTS
General Motors, LLC (GM) is recalling certain 2020 Chevrolet Bolt EV and 2021 GMC Canyon and Sierra 1500, 2500 and 3500, Yukon, Yukon XL, Cadillac Escalade and Escalade E…
TIRES
General Motors LLC (GM) is recalling certain 2020 Buick Enclave, Cadillac XT5, GMC Acadia and Chevrolet Traverse vehicles and 2020-2021 Chevrolet Silverado 1500, GMC Sier…
This does not say whether a particular car has an open, unrepaired recall. That depends on the VIN.
Before you buy a 2021 GMC Sierra 1500
Ask the seller whether the engine has ever been repaired or replaced, and whether the car has shown stalling, loss of power, rough idle, oil consumption or a check-engine light.
Drive it from a cold start and long enough to warm up. Many engine faults hide once the car is warm.
Get an independent pre-purchase inspection from a mechanic you choose, and tell them to focus on the engine.
7 recall campaigns on this model year. Whether a specific car still has one open depends on the VIN; the report checks that.
Ask for service records. A engine already replaced under warranty is a different car from one that was not.
Have the VIN?Paste it and get the full report for that car. First report free, then a 30-day pass covers a whole car search.
Experimental model-level information. This is not a vehicle inspection, vehicle-history
report, financial advice or purchase recommendation. It describes patterns across a model year, not the condition
of any individual vehicle.
