This preliminary informational (PI) bulletin provides information to dealership personnel that may be helpful when addressing underbody component corrosion with customers.
full bulletin at NHTSA ↗2021 GMC Terrain powertrain problems
moderate Owners of the 2021 GMC Terrain have filed 7 NHTSA complaints about the powertrain at roughly $2,500 to repair (U.S. federal records, as of July 2026). Source: NHTSA Office of Defects Investigation. See powertrain across all vehicles →
Complaints
7
Recalls
0
Avg fix
$2,500
| Model year | powertrain complaints |
|---|---|
| 2017 Terrain | 23 |
| 2018 Terrain | 39 |
| 2019 Terrain | 49 |
| 2020 Terrain | 23 |
| 2021 Terrain (this page) | 7 |
| 2022 Terrain | 8 |
| 2023 Terrain | 4 |
| 2024 Terrain | 20 |
| 2025 Terrain | 3 |
When does it fail?
Of the 7 powertrain complaints filed for the 2021 GMC Terrain, here's the actual mileage breakdown — failures cluster heaviest at 75,000-100,000 mi.
0-25k
25-50k
50-75k
75-100k
100-125k
125-150k
150k+
Each bar shows the share of total complaints filed at that mileage range. Peak failure window highlighted. Some owners report problems earlier; some make it well past 150,000 miles symptom-free. Maintenance habits and driving conditions shift the curve as much as mileage alone.
What stands out
Powertrain accounts for 21% of all owner complaints filed against this vehicle, across 4 categories tracked.
Is there a fix? Manufacturer service bulletins
The manufacturer has issued service bulletins covering powertrain on this vehicle — documented repair instructions, service campaigns, or warranty extensions sent to dealers. A TSB isn't a recall (it's not a free safety remedy), but it's the manufacturer acknowledging the issue and how to fix it.
This bulletin provides information on identifying Non-GM Engine Calibrations for Gasoline Engines using the Tech 2 or GDS 2.
full bulletin at NHTSA ↗This service bulletin provides information on the harmful effects of ethylene glycol in transmission fluid.
full bulletin at NHTSA ↗This service bulletin provides 9th gear operation information to respond to customers that may comment on transmission shift operation.
full bulletin at NHTSA ↗This service bulletin advises the tech that the rotational Clicking Noise Heard After Engine Shut Down may be normal characteristics of the vehicle.
full bulletin at NHTSA ↗Source: NHTSA manufacturer communications. Bring the bulletin number to your dealer or shop.
What owners are reporting 4 most recent
When accelerating from a stop between 35-45 mph the steering wheel shakes and you feel a vibration coming from the front wheels. I thought the wheels were loose and were about to come off.
My 2021 gmc terrain with 6000 miles on odometer. When driving up hill or going around corner transmission shudders so bad that it feels like front tires are coming off. I contacted the dealer and gm and was told there is a tsb for this complaint. GM and dealer acknowledged there was a problem but they didn't have a fix or known cause of problem
The contact owns a 2021 GMC Terrain. The contact stated that the transmission was previously replaced. The contact stated that upon starting the vehicle, the check engine warning light illuminated. The failure had occurred intermittently. Additionally, the contact stated that while driving approximately 15-20 MPH and depressing the accelerator pedal, the vehicle failed to respond for…
When driving car starting from a red light/getting on freeway or after making turn from a stop light when accelerating between 45 and 60 car shakes when shifting. Problem is getting worse. Car only has 6000 miles on it. I reported it to local gmc dealer and I was told GM is aware of the problem and they do not have a solution. They mentioned there is a TB out for several models that customers…
Had powertrain trouble with your 2021 GMC Terrain?
File a complaint with NHTSA → It's free, official, and how every report above got here — owner filings are the federal safety record this page is built on.
Common questions
How serious is the powertrain problem on the 2021 GMC Terrain?
It's a documented issue but not catastrophic. 7 complaints have been filed. Repairs average $2,500 and most owners catch it before it causes a breakdown.
At what mileage does the powertrain typically fail?
Based on the 7 complaints filed, powertrain issues most often appear around 57,422 miles. Some report problems earlier; some make it well past 150,000 with no symptoms. Maintenance habits matter — vehicles that received timely fluid services and were not regularly overworked tend to last longer.
What does it cost to fix?
Independent shops typically charge around $2,500 for powertrain repairs on this vehicle. Dealer pricing tends to run 20-40% higher. The exact figure depends on the specific failure mode, parts availability, and your local labor rates. If you're outside factory warranty, an extended service contract often covers this category.
Are there any recalls related to powertrain?
No active recalls currently cover powertrain issues on this vehicle. The complaints filed represent owner-reported failures that haven't risen to the level of a manufacturer-issued recall — but they're still worth knowing about before you buy or budget for repairs.
Related
Complaint and recall data sourced from the National Highway Traffic Safety Administration (NHTSA)
public records database. Verify the raw federal record at
nhtsa.gov/vehicle/2021/GMC/Terrain.
Severity ratings are derived from reported crashes, fires, injuries, and fatalities. Repair cost estimates are
independent-shop national averages and may differ in your area. Some links on this page are affiliate links.