GMC Sierra Complaints (2018)

371 consumer complaints on file.

#11670041June 29, 2025
ELECTRICAL SYSTEM, ENGINE, STEERING
I've had the vehicle service twice for the same incident power steering shut off in the middle of drive Vehicle shuts down almost smashed into a freeway wall. This has been to the dealership numerous times to fix it and they have not. We are in the tens of thousands of dollars in repair and still nothing is fixed I've had this vehicle for 5 years it's been In the shop for at least 3 I bought it with 30000 miles it only has 61000 on it right now The last repair lasted 10000 miles this repair only lasted 4000 I almost died and was left Is petrified.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11669494June 26, 2025
POWER TRAIN, ENGINE
Transmission has a shudder at lower speeds 1200 RMP area. Has been doing it since I bought the truck a few years ago. Took it back for warranty work and they claim this is a very common problem with this transmission. Claim that flushing the system would repair it, which it has not. Occasionally to will almost go out of gear, I have to try getting off the road safely to shut it off. After a few minutes, start it up and it will be back to normal. Also I’m on my 3rd starter. What appears to be another common issue with this model. Sometimes it fires right up, sometimes it’s very weak and others not at all and requires a jump start. All in all, recalls should’ve already been applied to these models. Pay way to much for junk!
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11667206June 16, 2025
POWER TRAIN
When driving the transmission will shift hard almost jumping forward, especially from a stopped position into 1st.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11666618June 12, 2025
ENGINE AND ENGINE COOLING, FUEL SYSTEM, GASOLINE
The contact owns a 2018 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed and depressing the accelerator pedal, the vehicle failed to accelerate as intended. The message "Reduced Power" was displayed, and the RPMs increased. Additionally, the vehicle jerked, and the contact noticed that there was smoke coming out of the exhaust pipe. The vehicle was driven to the contact's residence. The vehicle was taken to an independent mechanic, where it was diagnosed that the starter, the battery, the fuel pump, the oil pump, the oil pump sensors, and the fuel injectors had failed and needed to be replaced. The vehicle was repaired; however, the failure reoccurred. The contact stated that while driving at an undisclosed speed, the vehicle stalled. There was no warning light illuminated. The vehicle was able to restart; however, the failure recurred. The vehicle was driven to the contact's residence. The vehicle was not repaired. The manufacturer was made aware of the failure, but no assistance was provided. The failure mileage was approximately 133,742.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11665900June 9, 2025
POWER TRAIN, VEHICLE SPEED CONTROL
I am the original owner of a 2018 GMC Sierra 1500 with the 6.2L L86 engine and 8-speed 8L90 transmission. I began experiencing severe transmission shuddering and harsh shifting, especially at lower speeds or under light acceleration. When the issue occurs, I press the gas and the engine revs up to 6,000 RPM without reaching 20 MPH, making it extremely difficult — and dangerous — to merge into traffic or cross intersections. This issue has worsened over time and is now a critical safety concern, especially with children in the vehicle. I have researched this issue and found that many owners report the same transmission defect, and there is an open class action lawsuit and a GM Technical Service Bulletin (TSB #18-NA-355) describing the exact symptoms. The vehicle has become unsafe to drive. GMC should issue a recall or mandatory repair program for this known defect before someone is injured or killed.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11665102June 5, 2025
ELECTRICAL SYSTEM, ENGINE, POWER TRAIN
Engine lifters failed. Heard ticking noise first day truck was purchased that gradually got louder but was told by gmc service shop it was normal to hear the ticking noise. Also when cruise control is on and you are decending a hill the rpms raise and you lose engine compression this will cause your speed to drop to around 20 mph and has happened nunerous times.. as well when making a turn sometimes or just driving the vehicle turns off while in motion and you have to coast to the side of the road and turn the key off and back on to start driving agsin.. the loss of power is a complete blackout no dash.. no engine nothing. As result of the lifter issue the engine also hard shifts in and out of slow gears.. I have not driven my truck in about a year and still owe 22k on it. The issues with this vehicle are the same as the recalled 6.3 v8 engines.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11664711June 3, 2025
ENGINE
My vehicle was a well maintained 2018 GMC Sierra 1500. It has 58000 miles. I was driving in 30 mph zone thank God. Heard a loud boom and the truck lost power and shut off. I got out and oil was pouring out. I took it to the GMC dealership and they told me the engine failed. They didn’t know why or what caused the failure. But said they is a hole in the block and all they can say is something in the engine failed.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11663349May 28, 2025
ENGINE
Lifter when bad during engine start up. (known issue)
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11662760May 23, 2025
SERVICE BRAKES, HYDRAULIC
The contact owns a 2018 GMC Sierra 1500. The contact stated that while depressing the brake pedal, the brake pedal displayed more resistance than expected, causing the contact to have to apply more pressure while depressing the brake pedal. The contact stated that the braking distance was extended due to the failure. The vehicle was taken to the dealer who diagnosed that the brake vacuum pump had failed and needed to be replaced. The vehicle was not repaired. The contact became aware of NHTSA Campaign Number: 19V645000 (Service Brakes, Hydraulic); however, the VIN was not included. The manufacturer was informed of the failure and confirmed that the VIN was not included in the recall. The manufacturer referred the contact to the NHTSA Hotline to report the failure. The failure mileage was approximately 75,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11662326May 21, 2025
SERVICE BRAKES, HYDRAULIC
The contact owns a 2018 GMC Sierra 1500. The contact stated that while driving at various speeds, while depressing the brake pedal to slow down, the brake pedal lost pressure, and the vehicle experienced a reduction in braking power. The contact had to depress the brake pedal with additional force to properly slow the vehicle. There was no warning light illuminated; however, the message "Brake Assist" was displayed on the instrument panel. The local dealer was not contacted, and the vehicle was not diagnosed or repaired. The manufacturer was not notified of the failure. The approximate failure mileage was 135,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11660821May 14, 2025
ENGINE, POWER TRAIN
GM has discontinued a critical engine belt on the 2018 GMC Sierra 1500 5.3L eAssist. This makes the truck undrivable and unsafe to own, even though the vehicle is still under financing and only 7 years old. There is no available part, and no alternative has been offered by the manufacturer.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11658780May 4, 2025
ELECTRICAL SYSTEM
Apparently, GMC began using soy-based wire coatings approximately 10 years ago. The wiring harness on my vehicle has literally been eaten and destroyed by squirrels causing the entire electrical system to be compromised. Safety features have been especially affected including but not limited to air bags, windows being inoperable, door locks being stuck open or closed without a physical key, stabilitrak system arbitrarily shutting off, and windshield wipers working intermittently. Obviously, these are critical systems for the safe operation of this vehicle for the driver, passenger, and members of the public that share the roads. I have had the main harness repaired at a dealership (paid by insurance) but it remains an ongoing safety and financial issue. The dealership identified other portions of the electrical system still need repair and may further compromise safety. Not only were warning lights activated, approximately 10 in-dash messages were displayed warning of malfunction prior to dealership inspection and partial remediation.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11658709May 3, 2025
AIR BAGS, POWER TRAIN, UNKNOWN OR OTHER
The transmission would purge forward when shifting gears. The shifting was very rough. This vehicle had recently been in accident.
Crash:
Yes
Fire:
No
Injuries:
1
Deaths:
0
#11658155May 1, 2025
ELECTRICAL SYSTEM, ENGINE, STEERING
My engine and all electrical components including power steering and power brakes and all dashboard electrical will fail while driving. It is becoming more frequent and has almost caused an accident on numerous occasions to the point of not being able to drive safely on the highway any longer so now I only stay on surface streets and can't use for any out of town work. I usually do all of my own vehicle maintenance not been able to diagnose the culprit. Unfortunately I'm not able to afford the dealership diagnostic prices but open to any type of inspection.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11658311May 1, 2025
ENGINE
Spun main bearing in motor. Motor blown. It is available for inspection. GM mechanic inspected and quoted for new motor. Vehicle shut down going down interstate at 78 mph. No warning.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11657672April 29, 2025
ENGINE, POWER TRAIN, UNKNOWN OR OTHER
I have taken it in due to engine mounts 4 different times, transmission replaced and in October 2024 I took it in for issues I was experiencing like I had before my transmission went out. I did not get my truck back until almost Dec 2024 and that was due to there employee backing into the front end of my truck. So after all that my warranty was up Dec 24 2024 and then on April 16th 2025 I was driving my 2018 GMC Sierra 6.2l 1500 Denali 129,600 miles at approx 30 mph it was late so the streets were empty and we started to hear a knocking or what I thought at the time was a very bad exhaust leak. We parked and then we started to try to make it home very slowly which we did and it was not making to much noise. The next day I called GMC and explained they said bring it in. I towed it there to be safe but it did start and still ran at very slow speed. They called me and said that the lift side rockers/ lifters 1 failed and it was stuck due to a misfire and that the engine would need to be rebuilt and sent me over some very vague break down which looked like a lump sum price. I requested and better break down and got a screen shoot and that when he said that’s the best they can do. There were no engine lights on or warnings nothing at all. It also just got serviced at GMC for an oil change on February 27th 2025 along with some air filters. Today is April 29th and still waiting for the service manage to call and see if they can do anything to help out instead of charging full price. I will Attach pictures of the cost break down if possible. Thank you
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11656466April 24, 2025
POWER TRAIN
Transmission just would not go them all of a sudden it jersey really hard in second gear an start to pick up speed..cold starts it change gear really hard in second gearc often times slipping then going into gear really violently.. need fix asap dealer has service once with the issue, change fluid an stopped a while ago now issue is back an worst then before.. 44,785 vehicle should not operate this way.4×4 awd trans starts at 6500 to replace an go up to about 13200 to replace
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11652605April 3, 2025
ELECTRICAL SYSTEM, STEERING, FORWARD COLLISION AVOIDANCE: WARNINGS
While driving my truck and making low speed turns the dashboard (including center console) cuts off, along with my power steering. The truck has also shut off completely making u-turns causing me to almost crash. This also happened while driving around 60mph on the freeway, the entire dashboard went out, loss of steering, and truck shut off, almost causing an accident. When it does happen, it will cut out in 1 second intervals and steering will work again for 2 seconds then cut out again for 1 second, this causing me to stall. There are no check engine lights, or service lights that stay on. However, I will get a message stating: You are memory setting 3 in the system (wording may be different). In some cases the stabilitrak light will come on, the park assist warning stating it shut off comes on dash, and trailer break. I have a full service AUL warranty and had vehicle checked at certified dealership and no codes were recorded. I replaced battery and the problem is still happening. This is unsafe and should be part of the previous recall as my symptoms are the same exact symptoms as the other 2018 recall.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11650789March 26, 2025
ENGINE
The contact owns a 2018 GMC Sierra 1500. The contact stated that at start-up there was an abnormal ticking sound coming from the engine. There were no warning lights illuminated. The local dealer was contacted; however, the vehicle was not diagnosed. The contact was informed that the vehicle was out of warranty, and that the VIN was not under recall. The vehicle was not repaired. The manufacturer was not notified of the failure. The approximate failure mileage was 17,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11649082March 18, 2025
POWER TRAIN
The contact owns a 2018 GMC Sierra 1500. The contact stated that while attempting to accelerate from a stop, the vehicle failed to accelerate while depressing the accelerator pedal. No warning light was illuminated. The vehicle was taken to a local dealer, and the transmission was repaired under warranty. The contact stated that a year after the repair was completed, the failure reoccurred. The vehicle was not repaired after the most recent failure. The manufacturer was made aware of the failure. The failure mileage was approximately 94,600.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0

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