2021 GMC Terrain: engine and transmission complaints
HIGH COMPLAINT SIGNAL
47%
15 of 32 relevant owner complaints are about the engine, transmission or fuel system
47% of relevant owner complaints filed with NHTSA on the 2021 GMC Terrain are about the engine, transmission or fuel system. That is a model-level pattern, not bad luck.
Worse than 58% of the 1,230 model years we track (2010–2023).
Excludes 2 airbag, lighting and seat-belt recall complaints that would otherwise mask the signal (unadjusted: 44%).
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
POWER TRAIN04/29/2026
Automatic transmission solenoid control valve body got stuck open and ruined the whole transmission. This has been a reoccurring problem with these vehicles. Image is from a code read. Issue was confirmed by Gastorf Chevrolet, and an independent transmission shop.
ENGINE03/16/2026
The contact owns a 2021 GMC Terrain. The contact stated that while driving at various speeds, the vehicle hesitated while depressing the accelerator pedal, with a misfire coming from the engine. During the failure, the message "Engine Power Reduced" was displayed on the instrument panel. The vehicle was taken to a loca…
ENGINE,ENGINE AND ENGINE COOLING03/16/2026
Vehicle went into reduce engine power mode and check engine light came on. Vehicle has just over 60,000 miles. Code is telling me I need a new turbo and being quoted 1,500-3,000. I have read so many people having the same issue with needing a new turbo just after 60,000 miles
Three of 15 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 (2)
TIRES
General Motors, LLC (GM) is recalling certain 2021-2022 Chevrolet Equinox and GMC Terrain vehicles equipped with certain Hankook tires. The tires may have been manufactu…
CHILD SEAT:VEHICLE LATCH ANCHOR
General Motors, LLC (GM) is recalling certain 2020-2023 Chevrolet Equinox and GMC Terrain vehicles. The four rear-seat lower child seat LATCH anchorage bars may have exc…
This does not say whether a particular car has an open, unrepaired recall. That depends on the VIN.
Before you buy a 2021 GMC Terrain
Ask the seller whether the transmission has ever been repaired or replaced, and whether the car has shown shuddering, slipping, delayed or harsh shifts, or a whine at speed.
Drive it from a cold start and long enough to warm up. Many transmission 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 transmission.
2 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 transmission 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.