2018 GMC Sierra 1500 complaints

Noticed a scraping noise after new, recommended tires installed on my stock truck. Checked the door label to ensure correct tires installed, they were, returned to the tire facility and they recommended I ask a repair facility to investigate. Found that the tires are rubbing the upper control arm when fully turned left or right (both sides affected). Went online to discover that this is a common issue with the 2018 and similar GMC Sierra and Chevy Silverado trucks. This is a safety issue caused by a design deficiency. Two things can happen. One, the tire can fail. Two, the upper control arm could fail, causing the vehicle to be uncontrollable. This could be fixed by restricting the extreme left and right travel in the steering system or redesigning and replacing the upper control arm so it doesn’t interfere with the tire. This is an unacceptable safety issue caused by a design deficiency and needs to be addressed by NTSB now.

Radiator failed. Mileage is under 60k. It is currently being replaced by dealership. Dealer Representative noted that it is a fairly regular occurrence for these models. So much so that the dealership stocks this replacement radiator(hard for me to understand). There was no indicator lights to alert to this malfunction, it was noticed after work one afternoon when coolant was dripping out of the front of the vehicle.

The contact owns a 2018 GMC Sierra 1500. The contact stated while accelerating from a traffic light, the vehicle started hesitating. The contact stated no warning light was illuminated. The vehicle was not diagnosed or repaired. A dealer was not contacted. The manufacturer had not been informed of the failure. The failure mileage was approximately 99,000.

When the transmission is making changes, there is a shaking noise.

Transmission failure - the GM manufactured Torque converter on my truck failed to cause the transmission to fail. The internet is rife with stories of the failure of these transmissions on 2018 and 2019 GMC and Chevy Trucks.

THE MIDDLE REAR SEATBELT FAILS TO LOCK WHEN RETRACTED, THEREFORE I CANNOT USE MY GRANDCHILD'S BOOSTER SEAT. THE DEALERSHIP HAS ORDERED A REPLACEMENT, BUT COST NEARLY $300. I BOUGHT THE VEHICLE NEW IN DECEMBER 2018, BUT HAVE NEVER HAD TO USE THE REAL SEATBELT UNTIL NOW. THEREFORE I DID NOT KNOW IT DID NOT WORK PROPERLY UNTIL NOW.

8 speed transmission jerking, the torque convertor has been replaced 1 time already and having same issues as before. This time while in parking lot at store, was pulling into parking space, truck lundge forward during hard downshift hitting cart of person walking in front of truck. No damage and luckly barely hit the cart and not the person. I have also had the truck lunge forward when parking in my garage and hitting the garage wall in front. My truck is back at dealer again after hitting the cart in the parking lot. The 8 speed transmission issue from GM is a safety issue. My truck has already had first torque converter replaced and now having same issue with the new torque convertor

Noticed ongoing vibration sounds like you are running over rumble lines on road.

Braking vehicle will cause brake pedal to vibrate and become soft while pressing it and requires more effort to stop vehicle. Service brake assist light laminates on info system. I know there is a recall for this currently but my vehicle is not listed for this all though i have the same issues. Recall is N202300860.

The main harness under the truck , front to back . There was a separation from the conduit, wires exposed and were arcing. Truck would not start . I have since had it fixed . I just feel truck is not that old , to soon for a problem like this . And it cost a lot of money.

Hit a small bump driving 55mph on highway and had sudden complete power steering loss and extremely hard to turn. Drove to a safe location and shut down truck for 1 hour. Upon restart power steering was operating normal. Proceeded back on the freeway and as soon as I hit a small bump with driver's side front tire the same thing happened again complete power steering loss. Drove to dealership and waiting for explanation. The truck is not safe due to inability to turn the wheel without power steering. For someone with less strength, this could be deadly on anything besides a straight road, needing to turn a corner, or to avoid a collision.

I purchased my 2018 GMC Sierra 1500 pickup truck new in 2018. To date it only has 28K miles on it. I have never used the trailer breaking system that it came equipped with. On 12/24/22 we were traveling to a family function for Christmas. The "service trailer break system" warning message came on and the chime chimed continuously until I got to my destination, about an hour away. This chime was very distracting and there was no way to turn it off. After arriving at my destination I turned the truck off hoping it was just a fluke. When I started the truck back up the "service trailer break system" warning light and chime continued. It continued for an hour on my way home. Again, this was very distracting and I was unable to focus 100% of my attention on the road and my driving. Thank fully I made it home okay. On 12/27/22 I took the truck to my mechanic to have him take a look. He said he has heard of this issue with these pickups. His diagnostic confirmed that the trailer breaking switch (on the dash) was functioning properly but said that the chassis control module was likely the culprit. He replaced the control module and it had to be programed by a factory technician. After this part was replaced the warning light or chime does not come on anymore. I have the defective part for inspection and the bill totaling $1191.86 for the repair upon request.

I purchased this 2018 GMC pickup in May 2021. Starting in Nov 2022 I started getting a sporadic SERVICE TRAILER BRAKE SYSTEM warning light and chime. I have never towed a trailer using this trailer brake system on the vehicle, but the warnings come on sporadically. I have done some research and found this is not an isolated case as others have reported the same problem. Some owners have replaced the dashboard controller at their own expense, however this is now a well documented problem that goes beyond an isolated case. This is a defect of the trailer brake controller and should be recalled by GM at GM expense. It is a hazard to driving when the visual and audible chime come on sporadically. It's a distraction to safe driving and requires immediate intervention. I did advise my local dealer of the problem when the vehicle was serviced Dec 2022, however they did not have a technician available to work the problem. So I continue receiving the visual and audible warning every time I drive the vehicle. Please highlight this problem within your organization for a possible safety recall.

The contact owns a 2018 GMC Sierra 1500. The contact stated while driving 50 MPH, the vehicle started shaking and vibrating abnormally. There was no warning light illuminated. The vehicle was taken to the dealer to be diagnosed. The contact was informed that the transmission oil needed to be flushed. The vehicle was not repaired. The manufacturer was not contacted. The failure mileage was 71,000.

Sunroof shattered while driving on the interstate

Gas leak. My 2018 gmc sierra 1500 has been giving me two codes for evap leak small and large and i notice a black spot on my drive way under the gas tank wich in fact was gas. I can see the gas tank is wet but it comes from the top part of the gas tank. I been looking for recalls on this but there isnt any for this specific year of GMC sierra 1500 slt.

The contact owns a 2018 GMC Sierra 1500. The contact stated that while driving at an undetermined speed, the vehicle was shaking while shifting gears. The contact stated while shifting from four cylinders to eight cylinders, the rear-end was shaking violently. The hood latch warning light was illuminated. The vehicle was taken to the local dealer where it was diagnosed and determined that the tires needed to be replaced. The tires were replaced three times however, the failure persisted. The manufacturer was not contacted. The failure mileage was approximately 50,000.

Breaks are not working

The contact owns a 2018 GMC Sierra 1500. The contact stated that while pulling up to park the vehicle at approximately 2 MPH, the power steering failed causing the contact to use an excessive an extra amount of effort while maneuvering the steering wheel to park the vehicle. The power steering assist warning light was illuminated. The contact took the vehicle to the dealer to be diagnosed. The contact was informed that the steering assembly and steering gear needed to be replaced. The vehicle was repaired. The manufacturer was made aware of the failure and filed a case. The approximate failure mileage was 39,000.

Experienced heavy vibration or shudder through transmission once fluid got to around 145 degrees. Also transmission has rough shift on the first shift of a drive cycle. When I started to research I found many of the same issues reported with 8 speed transmissions. I’ve also read about the issues with the lifters not working for the active fuel management system though I haven’t experienced that yet. The replaced my transmission fluid at the dealership under the powertrain warranty. This issue showed up at around 35,000 miles, so I am very worried about the safety and reliability of this engine and transmission.

In short, the moonroof of my vehicle spontaneously exploded into a million pieces one morning while driving.

While driving 35 miles per hour in the early morning hours I came to a 4-way intersection and applied the brakes slowly. Suddenly, I lost all power in the brakes and the steering wheel locked up. The lights, and stereo remained on, and my dash board display immediately showed a red check engine light. I immediately turn on my hazard lights, turned the ignition key off and tried to restart the truck. There was no clicking sounds. The truck would not start but the lights dimmed and the dash display now showed an intermittent yellow, flickering check engine light. After roughly 30 minutes while waiting for AAA to arrive I tried the ignition key and the truck started up with a red check engine light. Rather than attempting to drive I had AAA tow my vehicle to the Chevrolet dealership where I purchased the truck.

My truck has a severe vibration or shake extremely bad at 60mph and up.i have tried new tires, front end alignment, and several different shops have told me they don't know what it is drive shaft or axels

Air conditioning condenser failed at about 48,000 miles. Seems to be a common problem that is a design defect.

Received an error on the dash saying "Service Brake Assist". At the same time the brake pedal became very stiff and braking power was decreased significantly. I have received this same message and brake pedal stiffness with reduced braking power three times in the last 4 days.

Transmission System, hard shifts and shaking causing vehicle to down shift hard and throw itself forward almost causing an accident when coming to a stop, when vehicle was taken into service they did not diagnose the vehicle for this problem, while driving vehicle shifted down so hard causing vehicle to be stuck in only 1st gear and would not shift out of 1st gear

The service alert for the trailer brakes keeps going off constantly and continues to go off persistently almost making the vehicle undriveable. I was informed to file a complaint with your company by my local dealership as this is a recurring issue with GMC trucks.

*A message and alarm kept going off on our truck "Service Trailer Brake". We are not towing a trailer, nor had we had a trailer hooked to this vehicle since 2019. It began only going off occasionally, but within a few weeks it was going off constantly. It would show repeatedly on the dash and the alarm would sound over and over. Trying to turn off the system was not successful, no matter how many times we hit dismiss. It was totally distracting and worrisome that something was wrong with our braking system in general. *The constant alarm and dash display made driving a very distracted experience. It is so loud that you cannot hear other outside noises. We were also concerned about the safety of our regular braking system. *I called the dealer where our truck is regularly serviced. They immediately said "Is it the Trailer Assist Alarm?," so it was obvious that this is happening to other owners regularly. It took several days to get in for an appointment. The shop mgr helped us to locate and pull the alarm fuse to stop the noise, so we could drive it to the dealership later in the week. The display was still going off when I pulled the truck into the dealership, as it has done all the way there (17miles from my home). *It was inspected by the GM dealership (Schwarz, INC. Honesdale, PA) and the defective switch was replaced at a cost to us of $127.14 on 08/11/2022. *This issue started several months ago (Feb 2022?), but it was a one time thing. So, we thought it was just a fluke

I am getting a service alert for the Trailer Brake System. It is constant and loud and distracting and a significant safety hazard, not only because of the distraction, but also because it renders trailer brakes completely useless

THE SPEED OF THE TRUCK WILL NOT INCREASE. THE RPMS GOES REALLY HIGH AND THE TRUCK WILL NOT MOVE INTO THE NEXT GEAR. THE REAR END OF TRUCK VIBRATES. I TOOK THIS TO THE DEALER AND WAS TOLD IT IS THE TRANSMISSION FLUID IS FAULTY. THE CHECK ENGINE LIGHT DOES COME ON. I DID NOT HAVE THE NEW TRANSMISSION FLUID CHANGED BECAUSE DEALER SAID IS COST $300 FOR THE FLUID AND $100 FOR THE LABOR AND $168 FOR THE DIAGNOSTICS. SO I STILL HAVE THE SAME PROBLEM. ALSO TOLD YOU CAN NOT PURCHASE THIS TRANSMISSION FLUID NO WHERE BUT GMC.

Constantly getting “service trailer brakes system “

The light in the dashboard gose dark and it gives me a warning collision alert and the tiers they spin out of control when turning or when I I’m driving I think it’s the tiers they have a lot of tread still…

Informant system and instrument clust/panel starts to change with nothing be clicked. Starts to phantom change everything which is deters from paying attention to actual driving becoming a safety hazard. Dealership has tried to update the software and still does not work.

Transmission slams into gear in drive and reverse while driving it will slam into gear. And occasionally at speeds under 5 going up a hill it will have no power and struggle. I have 59000 miles on it last year around 53000 miles they did a transmission flush and that fixed it for about 9 months. Just took it back in they reprogrammed the transmission and it no longer slams In drive and reverse but still knocks back-and-forth while driving.

I was stopped at a fast food drive thru and then I tried to go to the next window and the truck wouldn’t move at all it will just rev so I put it in parked turned off the truck and turn it back on put it on drive and was able to move for like 40 ft then it did it again so I had it towed to my home

Trailer brake modulator on 2018 GMC Sierra does not consistently signal trail brakes to work when needed on our 7,500 pound RV trailer. GMC dealer eventually found that the battery cables were undersized as installed with the factory towing package on the 2018 GMC Sierra. The undersized battery cables do not consistently deliver adequate voltage to the trailer brake modulator on the GMC Sierra, so inconsistent electric brake function for our 7,500 pound RV trailer. Dealer had difficulty diagnosing the problem as being the wrong factory-installed battery cables to go with the factory-installed trailer towing package. So it cost us $1,600 to have the GMC dealer correct a problem caused by the GMC factory installing undersized battery cables. Fortunately, this did not result in a collision for us, but it might for someone else. Our 2018 GMC Sierra kept sending vague, randomly timed warnings to the dashboard to "Check Trailer Wiring." Very frightening, dangerous and costly (for us) mistake by GMC. Will the brakes work this time, or fail on the way home? Problem started in 2021 RV season, but took awhile for us to recognize the need to take to the GMC dealer for them to diagnose base cause. Took time for us to experiment changing trailer wiring connector on bumper and trailer brake control on the dash. Work for awhile, then fail. Work for awhile, then fail. Arrrrgh! Ask GMC to put more adequate battery cables on ALL their vehicles, please.

I have a 2018 GMC Sierra Denali. I started having problems with the 8-speed transmission at 18,000 miles. The vehicle has been to the dealership for a transmission fluid flush, a transmission relearn, a 5-week valve body replacement, two more trips to the dealership where the truck did not malfunction for them. I have had issues with an air leak on the driver side front door as well. That issue has not been resolved as well. I spent over $60,000 for the truck and have had nothing but problems. I have brought it to General Motors attention and all I would do is get a run around and no results. I was told that there is nothing more that they can do. I am beside myself and just sick as I do not know what to do. I bought a brand new vehicle in order to not have problems compared to a used one.

SERVICE TRAILER BRAKE SYSTEM - warning

The radiator developed a leak on the drivers side. This caused a loss in antifreeze.

Leak detected in the engine oil cooling lines, requiring replacement.

I was driving down the highway when my vehicle loss control of operation and check engine light came on. After taking it to the GMC dealership it was determined to be a bad lifter in the motor. The garage had to take the motor completely apart to repair a bent rod and cylinder in the motor. There are numerous reports and a pending class action lawsuit concerning this device in the GMC Sierra trucks and other GMC vehicles. The lifters in the cylinder of this motor are designed to switch the engine from V4 to V6 to save on gasoline. My vehicle has been repaired by the GMC garage but I've seen reports of this problem repeatedly happening in these vehicles and it causes me great concern because if there is a lot of traffic in the area I could get hit or cause an accident by not being able to operate the truck. My vehicle is available for inspection upon request. The safety of myself and others is put at risk because the sudden equipment breakdown could cause an accident. The problem was confirmed by the dealer. No other parties have inspected the vehicle. No warning lamps went off prior to this happening and the vehicle is only a 2018 and only has 36,000 miles on it.

The left rear tail light assembly is subject to direct wheel spray resulting in premature corrosion and failure of the lightbulb and wiring harness. Failure first occurred Within 18 months of ownership. I cleaned the contacts and packed the connection with dielectric grease. However after three years the bulb connection is now totally corroded and the circuit has failed requiring harness replacement. The problem is so widespread, replacement wiring harnesses for the left rear tail light assembly are out of stock and unavailable from GM parts. I am now using the vehicle without operating right rear turn signals. GM-trucks.com is an owners chat room with many entries about this problem. [XXX], BSME, P.E. SAE INFORMATION Redacted PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6).

On 2/26/22, approximately 24,000 miles on the vehicle, while traveling on the Interstate a warning popped up in the display that the power steering had failed and to operate the vehicle with caution. Immediately I noticed I had no power steering, and the vehicle was extremely hard to steer. I exited the interstate and turned the vehicle off. I conducted a visual inspection; no issues were immediately apparent. After several minutes I started the vehicle, and the power steering began functioning. I conducted an Internet search and learned this is a common issue for GMC trucks, previously resulting in numerous crashes and over one million vehicles being recalled. NHTSA campaign number: 18V586, GM’s number for the recall 18289. 3/1/22, I contacted GM customer care and was advised my vehicle was not part of the recall. I was advised to take the vehicle to a GM service center, at my cost. 3/1/22, I contacted Mossy GMC of Picayune, MS, and spoke with a technician, who advised the issue is usually due to a drop in voltage and advised me to replace the battery. 3/19/22, replaced the battery. 3/30/22, upon startup the power steering again failed. I turned the vehicle on and off several times, and the power steering began functioning. 3/30/22, went to Mossy of Picayune, spoke with a technician, who advised he was quite familiar with the issue, stating this is a common problem with GMC trucks, he advised to replace the battery. Told him I replaced the battery on 3/19/22, he stated I wou

“Service- trailer brake system” light keeps coming on. It is super repetitive. It comes on about every 30 seconds. It’s a loud beep that lasts quite a few seconds. Eventually, the beeping did not stop until the truck was stopped. Truck was just bought yesterday. Happens at any speed, even when stopped.

Yesterday afternoon I heard a beeping noise that was persistent and it said trailer brake check the same alert showed up today making it impossible to drive safely with the alert popping up every min

The contact owns a 2018 GMC Sierra 1500. The contact stated while driving approximately 35 MPH, the assist brake warning light was illuminated and the contact had to depress the brake pedal to the floor to stop the vehicle. The contact took the vehicle to the local dealer, where it was diagnosed with needing the vacuum pump to be replaced. The vehicle was not repaired but was pending repairs. Upon investigation, the contact associated the failure with NHTSA Campaign Number: 20V603000 (Service Brakes, Hydraulic). The manufacturer had not been informed of the failure. The failure mileage was approximately 37,000.

The contact owns a 2018 GMC Sierra 1500. The contact stated that while driving at various speeds, the vehicle experienced shifting while shifting into a lower gear, causing the vehicle to suddenly lurch forward. The cause of the failure was not determined. The local dealer was notified of the failure but no assistance was offered. The manufacturer was not contacted. The failure mileage was 50,000.

Transmission shrudder with low mileage

The contact owns a 2018 GMC Sierra 1500. The contact stated that the seat belt straps for the rear driver’s and passenger’s side seats would no longer retract and were stuck between the seat cushions. The cause of the failure was not determined however, the local dealer informed the contact that the seat belt retractors were likely defective and would need to be replaced. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was 60,000.

When operating my truck two days ago, I smelled something burning. I then noticed a small plume of white smoke coming from the rear driver's side window area. I then noticed my rear defroster was on, which I shut of right of way. About 30 seconds later, I heard a loud pop and I noticed the rear driver's side portion of the window was shattered. I brought my truck to the dealership and they said they could not figure out what happened. I believe it is tied to a prior recall, but they said my truck was found not to have any issues at that time. I believe there is a direct correlation with the recall issued and what happened a couple of days ago.