GMC Terrain harsh shifting problems

Filed Apr 16, 2026 · Suspension · 14 miles · NY

The contact owns a 2026 GMC Terrain. The contact stated that there was an abnormal clunking sound coming from the front driver’s side suspension while driving over bumps in the roadway, and while braking and turning the steering wheel. No warning lights were illuminated. The vehicle was taken to a local dealer, where a test drive was performed; however, the dealer was unable to determine the cause of the failure. The vehicle was not diagnosed or repaired. The manufacturer was not notified of the failure. The approximate failure mileage was 14.

Filed Feb 2, 2026 · Transmission · PA

Transmission dropped complete out of gear while driving. Got vehicle moving again. Took to dealership. Found complete internal transmission failure at 6779 miles. Transmission replaced with new unit. New transmission has erratic / hard shifts. Found replacement transmission leaking fluid due to front pump / porous case at 14800 miles. Customer Satisfaction Program N232433890 issued May 16, 2024

Filed Jul 8, 2025 · Brakes, Transmission · PA

Accelerating from a stopped position into a busy intersection heard a loud clunk come from engine bay resulting in immediate "Reduced engine power" warning and stall condition. Was able to push vehicle onto the side of the road. Engine would not restart and a tow truck was called. Vehicle towed to local dealership who discovered that Vacuum Pump had failed resulting in sheering off of the exhaust camshaft. Dealers recommended fix was to replace vacuum pump and camshaft at around $4,000 but could not guarantee no debris had gotten into valve body resulting in engine failure so stated they could replace with used engine for 8500. Second vacuum pump to blow on this vehicle, first at 35k miles and replaced under warranty, this incident at just under 80k miles. Could not afford repairs and vehicle has sat for nearly 2.5 years. Contacted GM many times over that time period to get no assistance, only the offer of a small discount on a new vehicle. This incident could have proven fatal if happening at highway speeds since it stalls engine out and makes braking nearly impossible. Both GM and the NHSTA have really flunked on this one, should have been recalled during first complaints in 2020. I will continue to file complaints here on NHSTA and with GM until the cows come home.

Filed Jun 18, 2021 · Engine · IN

My GMC Terrain makes a clunking noise under the hood when I accelerate and go into a lower gear. Does it mostly going up hills but also even on flat road.

Filed Sep 14, 2020 · VA

Transmission first to second has a hard shift, this happens a lot with the SUV having 33,106 miles

Filed Jun 22, 2018 · Airbags, Engine · 2,500 miles · NE

First issue with the vehicle was a separation of the dash near and around the passenger side airbag. Unknown at this time if the airbag has been compromised. I won't know until the vehicle would be involved in an accident. The second issue involves the vehicle while in park. I am able to push the vehicle and it will actually move forward. There is also a very hard shift while the vehicle is in motion. This occurs usually between 2k and 3 k rpms. The vehicle will actually jerk as it is trying to shift.

Filed Aug 10, 2016 · Transmission · 47,000 miles · NY

The car did not change gears at the ?proper? Time, and then when the brakes were applied or acceleration was ended the car would hard shift to the next gear. It is almost as if the gear was locked into place by the acceleration. Because of this shifting issue, it feels like the car is bucking, which can be a potential safety issue for myself and my family. Issue mainly occurs on slope like conditions in the 25 to 35 mile per hour range, our car is up to date on all recalls per dealer, they were unable to replicate the issue, but replaced the shift stick, this also prevents the car from shifting gears by accident I.e. Without the button pushed, this repair has corrected the manual shifting issue. The automatic shift issue still remainsthe car has less then 50k miles. The issue was 1st discovered in the mountains of pa on the 80 hwy the stickiness was between all gears but mostly 1st/2nd and 3nd/4nd since we are back in the city we can only deal with 1/2 gear on the hwy and this problem persists. When doing basic research on this issue I noticed that others experienced a similar problem in 2011 shortly after the cars release, but a flash to the emc "fixed" the problem. Our dealer says that all recalls and software are up to date. Last occurrence 7/26/16 we dont drive the car much since then.

Filed Mar 8, 2016 · Acceleration, Driver assistance · 45,000 miles · CA

Summary: I had to decide to brake or shoot through a yellow light, going about 35 MPH, I braked! All of a sudden I heard a clunk and then alarm ding from the dash as well as message "service stabiltrak" then "reduced engine power". I was unable to go any faster than 25mph. I drove in this mode for about 2 miles taking the back streets to my destination. At destination shut vehicle off to see if this would reset something, it did! It was super scary. So now terrified to brake hard.

Filed Dec 16, 2013 · Acceleration, Electrical · 50,000 miles · MO

Our vehicle has experienced the rough idle and hard/stalled shifting since we bought it in 2011. It has been reviewed by the dealership and we were told a recent recall would fix the issue. It did not and these issues have continued. Recently, this issue happened again, followed by the check engine light turning on, followed by (a few hours later) the engine going into "reduced engine mode" and the entire vehicle shaking uncontrollably with thumping noises coming from the front of the vehicle. The vehicle was stopped and restarted and within a few miles, this same issue happened again, which was very difficult to handle and very unsafe for travel in the city. We had to get a tow to the dealership and the service department at the dealership we bought this from says the throttle positions sensor is defective and needs replaced as well as there is a misfire in the injectors due to carbon buildup in the fuel line. None of these repairs are covered under the power train warranty, and this vehicle only has 50,000 miles on it currently. Upon research of these part, symptoms of this part going out are stalled shifting or hard shifting, as well as rough idling. Please research this case as I feel this is a more universal problem that has yet to be addressed properly.

Filed May 7, 2013 · Engine, Transmission · 2,000 miles · CT

About a month after purchasing this brand new vehicle, there were several times that after starting the car & putting it into gear, it stalled. There has also been times that after driving it for a while & coming to a stop sign, then getting ready to pull out into traffic, it either stalls or hesitates. There were a few close calls where there could have been a major accident. Taking this to the dealer did nothing. They said they have heard of this before, but unless it did it at their dealership, they couldn't fix the problem. Another issue I have had is that many times the transmission doesn't shift properly & it revs up more than it should before actually shifting & when it does, there is a major clunk. I have owned many cars in my lifetime, this car always on startup, makes a terrible noise at first which to me sounds like it's not getting any oil or that the bearings have a problem. That noise goes away after a few seconds. Another issue I have, as do all other terrain owners, is that the sticker on the window from gm when buying this car, stated that this car would get 23 mpg city, & 32 mpg highway. Most all my miles are highway miles, & the most I ever get is 22 mpg. This was the main reason for buying this car in the first place. I think gm should be held accountable for this grossly mis-representation of what I would be getting for gas mileage. I am not that wealthy where I can just go out & buy a new car every year, but am fearful that with the car stalling out whenever it feels like, that I may have an accident. I am also not thrilled with the noise it make when I start it, & wonder how long before it doesn't run. I now have 36,000 miles on it with these issues, my last vehicle that I traded in for this had 250,000 trouble free miles. Gm needs to buy this back, or lifetime warranty on motor along with free gas to make up for the 10 mpg I'm not getting.