2018 GMC Sierra 1500 Problems
Owner-reported complaints filed with NHTSA, grouped by component
Data refreshed
What this page shows
Everything below is an owner-reported complaint submitted to NHTSA about the 2018 GMC Sierra 1500, grouped by the component NHTSA recorded on the report. These are not confirmed defects, and they are not recalls. NHTSA does not verify most reports before publishing them, and a category with more reports in it is not evidence that a part is defective.
Complaints are reports submitted by owners and drivers to NHTSA. They are not verified and do not establish that a defect exists.
Reports by component
Ranked by how many owner reports name each component category
- Powertrain (other)12331.7%
- Engine6917.8%
- Electrical4311.1%
- Brakes4311.1%
- Steering307.7%
- Driver assistance133.4%
- Fuel system112.8%
- Suspension102.6%
- Airbags82.1%
- Other / unspecified71.8%
- Visibility61.5%
- Body & structure61.5%
- Seat belts51.3%
- Tires & wheels51.3%
- Exterior lighting30.8%
- Transmission30.8%
- Interior & seats20.5%
- Heating & air conditioning10.3%
Percentages are of component mentions. A single complaint can name more than one component, so these do not sum to the total complaint count.
Each component in detail
What the reports in each category say, in the owners' own words
Powertrain (other)
Powertrain reports that are not specifically the engine or transmission — driveshafts, axles, transfer cases and differentials.
From owner reports, verbatim
Vehicle Details: 2018 GMC Sierra 1500 Z72 4x4, 5.3L V8 EcoTec3 engine, VIN: [XXX] Mileage at time of incident: 220,000 miles Location: [e.g., Little Rock, Arkansas area or specific road/highway – please provide if desired] What happened: The 5.3L V8 engine’s hydraulic roller lifters failed. One or more lifters collapsed, stuck, or lost proper oil pressure/operation. This led to improper valvetrain function, causing loud ticking/knocking noises, cylinder misfires, significant loss of engine power and performance, and internal engine damage (such as camshaft lobe wear or related components). Component or system that failed or malfunctioned: Hydraulic valve lifters (camshaft followers) in the engine valvetrain, associated with the Active Fuel Management (AFM) system. The failed lifter(s) and related components are available for inspection upon request. How safety was put at risk: The engine malfunction resulted in sudden or progressive power loss and misfiring while driving. This reduced the vehicle’s ability to accelerate or maintain speed, especially in traffic or on highways, creating a hazardous situation that put my safety and the safety of other road users at risk of collision or breakdown. No accident or injuries occurred , or other symptoms prior to the failure with details recall, e.g., ticking noise timeline, misfires Has the problem been reproduced or confirmed by a dealer or independent service center? “Yes, confirmed by shop inspection” Has the vehicle or component been inspected by the manufacturer, police, insurance representatives or others? [Yes] Additional notes: Repair estimate is approximately $20,000 (likely due to extent of internal damage requiring major engine work or replacement). This failure aligns with a well-documented issue in GM 5.3L engines equipped with AFM. Vehicle status parked INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
The transmission has always been rough. It has now gone out at 75,000 miles. This transmission issue really seemed to get worse about 50,000 miles. But when I called the dealer, they said they were backed up and couldn't get to it for 9-12 weeks (Covid excuses at that point). Then, it really had an issue going down a large grade into [XXX] . But the issues seemed fairly intermittent. I had an independent shop who said it was hard to tell if it was intermittent. They didn't find metal shavings at the time. ADDITIONALLY, it has also always been a little rough driving. A mechanic looking at it today told me there are no sway bar links at all. This truck has not been modified. This had to have come off the line faulty. Among all the other things. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
Engine
Reports naming the engine itself — including stalling, misfires, oil consumption, cooling and internal engine components.
From owner reports, verbatim
Head gasket failure and overheating. After fixed, power steering has just failed during driving. Will have to have it towed to shop
ENGINE FAILURE, 5/3/22, 23,987 MILES, ALL LIFTERS WAS REPLACED UNDER WARRANTY, ENGINE FAILURE, 7/6/26, 46004 MILES, TOOK TRUCK IN FOR OIL CHANGE AND WHEN RETURNED HAD A TICKING NOISE. DEALERSHIP NOTIFIED ME THAT CAMSHAFT ISSUES AND METAL DETECTED IN OIL. ENGINE NEEDS REPLACED. 6.2 V8 2018. TURPIN MOTORS, GENESEO, IL HAS DONE ALL SERIVCE ON TRUCK. NO WARNING LIGHTS OR CODES. VEHICLE IS IN MY GARAGE AND AVAILABLE FOR INSPECTION. I OPENED CASE WITH GM #105652237. DEALERSHIP OPENED CASE ON GM PORTAL ALSO. RESPONSE FROM GM IS THAT TRUCK IS OUT OF WARRANTY
Electrical
Reports naming the electrical system — wiring, battery, charging, control modules, infotainment and electrical accessories.
From owner reports, verbatim
1. Electronic power steering modular issue. My 2018 GMC SEIRRA 1500 CREW CAB JUST LOST ALL POWER STEERING. THEN WHEN I PARK IT. Assist notifications come on, ABS notices, BRAKE light stays on, trailer/tow notifications, trailer assist, parking brake, etc SUDDENLY A LOUD thump & feels like the whole truck just drops like 5” inches, settling. I cannot afford an inspection (ID theft in 2025, compromised all accts & all credit cards) BUT. It IS available as long as cost is covered by YOU !! 2. Lucky it happened in a grocery store parking lot. However not expecting power steering to go out, almost hit a pedestrian. 3. No it has not Ben inspected yet I can’t afford the bill 4. No it has not been reported what for I didn’t hit anybody and the cops in this area they could give her rats ass they don’t make a report the question you like you’re like a criminal. 5. No warnings or anything until it happened that day leaving the grocery store. There is absolutely no notification it was gonna happen. It ran fine when I parked it to grocery shop Come back out & I could barely back out to leave. I can lift up my had fatboy if needed so I’m sure turning a steering wheel…. lol Thnx a lot If I could figure out what part needs to be changed out or you could cover the parts needed. I do work in cars or have in the past, I don’t like the new ones, but this seems simple enough if I knew exactly what part I needed to pull out change out or I see that there’s recalls on previous vehicles and GMC after2020- 24 but I don’t see 2018 didn’t happen so I like to say whoever created that electronic steering can take that module along with the harness and they know exactly where they can put it don’t they I’m just saying as a used to be not sure now a GMC supporter, but I’m starting to think twice now if I
Odometer Fraud. The contact purchased a 2018 GMC Sierra 1500. The contact discovered that there was a mileage discrepancy after the purchase. The vehicle was a private sale. At the time of purchase, the vehicle mileage was 72,000. It was later discovered later that the mileage was 241,556.
Brakes
Reports naming service brakes, the antilock braking system, brake hoses, master cylinders or the parking brake.
From owner reports, verbatim
Incident description: On three occasion I have had the same catastrophic Engine failure putting myself and my family along with the general public in harms way. Starting March of 2022 while driving at approximately 60 MPH on the West Shore Expressway my truck experienced a sudden and total loss of motor power. My engine stalled out and I lost my ability to safety steer and stop my vehicle. This all happened during rush hour while driving in the left lane of traffic. This sudden loss of power forced me to maneuver the vehicle to the right shoulder of the expressway across the right lane of traffic. As there was no shoulder to pull over on the left side of the highway. This created an immediate crash risk for myself and other drivers. Upon inspection at the authorized GMC dealership where I purchased the truck new, a certified mechanic determined that the engine experienced a complete failure requiring replacement or rebuilding of the engine. I paid to have the engine rebuilt at the dealership. The second instance was similar to the above incident. Once again I paid for the repair. The third instance was more dangerous as when my trucks engine failed it almost caused an accident. As of today my truck is still sitting in the dealership for over 6 months and no one from the dealership or manufacturer will give me an answer on what has to be done now. This patter of sudden repeated engine failure clearly indicates a systemic safety defect that extends beyond normal wear and tear. I urge the NHTSA to open a defect investigation into the 2018 GMC Sierra 1500 engine systems.
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.
Steering
Reports naming the steering system — racks, columns, power-steering assist and steering linkage.
From owner reports, verbatim
Head gasket failure and overheating. After fixed, power steering has just failed during driving. Will have to have it towed to shop
Power steering went out for 2-3 seconds as I was making a turn into a street , this happened twice to be exact
Driver assistance
Reports naming forward-collision avoidance, lane keeping, back-over prevention, cruise control and related electronic driver-assistance systems.
From owner reports, verbatim
ENGINE FAILURE, 5/3/22, 23,987 MILES, ALL LIFTERS WAS REPLACED UNDER WARRANTY, ENGINE FAILURE, 7/6/26, 46004 MILES, TOOK TRUCK IN FOR OIL CHANGE AND WHEN RETURNED HAD A TICKING NOISE. DEALERSHIP NOTIFIED ME THAT CAMSHAFT ISSUES AND METAL DETECTED IN OIL. ENGINE NEEDS REPLACED. 6.2 V8 2018. TURPIN MOTORS, GENESEO, IL HAS DONE ALL SERIVCE ON TRUCK. NO WARNING LIGHTS OR CODES. VEHICLE IS IN MY GARAGE AND AVAILABLE FOR INSPECTION. I OPENED CASE WITH GM #105652237. DEALERSHIP OPENED CASE ON GM PORTAL ALSO. RESPONSE FROM GM IS THAT TRUCK IS OUT OF WARRANTY
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.
Fuel system
Reports naming fuel storage or delivery — tanks, pumps, lines, injectors and fuel leaks.
From owner reports, verbatim
I own a $35,000 2018 gmc Sierra 1500 6.2l V8 4x4 Denali, which is currently down due to engine failure while I was driving down the road.. never had a check engine light on the dash. Haven't had the truck a year before it quit. Rods knocking, crankshaft bearings, loss of power, high rpm with little acceleration. I could have the peddle down to the floor and would barely get to 20 mph.. the motor would jump so bad, you would think it's going to jump out the truck. I have replaced several parts on the truck, including oil pump, filter, solenoid valve sensor, fuel pump, injectors, and sensors, battery, starter a couple times. Did all that replacing for it to get worse and finally quit while driving.. I was stranded in the middle of the road.. IV reported it to the Recall people, but nothing helped. I have taken my vehicle to Express Chevrolet and they did a diagnostic test, which I provided the list they gave me below. When I took it to them, I was using Endurance Warranty, but they denied my claim due to the issues and they didn't cover them. At the time, the motor was still jumping, but smoke was coming out the tailpipe extremely bad, the truck was jerking and jumping. After replacing everything I listed, the truck got worse, started screeching and knocking loudly, loss of engine power, little acceleration. The day the motor quit on me while driving, I got the mph up to about 55-60 and it just quit, and hasn't started back since.
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.
Suspension
Reports naming suspension components — springs, struts, shocks, control arms and related hardware.
From owner reports, verbatim
The transmission has always been rough. It has now gone out at 75,000 miles. This transmission issue really seemed to get worse about 50,000 miles. But when I called the dealer, they said they were backed up and couldn't get to it for 9-12 weeks (Covid excuses at that point). Then, it really had an issue going down a large grade into [XXX] . But the issues seemed fairly intermittent. I had an independent shop who said it was hard to tell if it was intermittent. They didn't find metal shavings at the time. ADDITIONALLY, it has also always been a little rough driving. A mechanic looking at it today told me there are no sway bar links at all. This truck has not been modified. This had to have come off the line faulty. Among all the other things. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
1. Electronic power steering modular issue. My 2018 GMC SEIRRA 1500 CREW CAB JUST LOST ALL POWER STEERING. THEN WHEN I PARK IT. Assist notifications come on, ABS notices, BRAKE light stays on, trailer/tow notifications, trailer assist, parking brake, etc SUDDENLY A LOUD thump & feels like the whole truck just drops like 5” inches, settling. I cannot afford an inspection (ID theft in 2025, compromised all accts & all credit cards) BUT. It IS available as long as cost is covered by YOU !! 2. Lucky it happened in a grocery store parking lot. However not expecting power steering to go out, almost hit a pedestrian. 3. No it has not Ben inspected yet I can’t afford the bill 4. No it has not been reported what for I didn’t hit anybody and the cops in this area they could give her rats ass they don’t make a report the question you like you’re like a criminal. 5. No warnings or anything until it happened that day leaving the grocery store. There is absolutely no notification it was gonna happen. It ran fine when I parked it to grocery shop Come back out & I could barely back out to leave. I can lift up my had fatboy if needed so I’m sure turning a steering wheel…. lol Thnx a lot If I could figure out what part needs to be changed out or you could cover the parts needed. I do work in cars or have in the past, I don’t like the new ones, but this seems simple enough if I knew exactly what part I needed to pull out change out or I see that there’s recalls on previous vehicles and GMC after2020- 24 but I don’t see 2018 didn’t happen so I like to say whoever created that electronic steering can take that module along with the harness and they know exactly where they can put it don’t they I’m just saying as a used to be not sure now a GMC supporter, but I’m starting to think twice now if I
Airbags
Reports naming the air-bag system — deployment behaviour, inflators, sensors and warning lights.
From owner reports, verbatim
The contact owns a 2018 GMC Sierra 1500. The contact stated that while driving approximately 45 MPH on bumpy terrain, the driver’s and passenger’s side curtain air bags deployed unexpectedly. No warning light was illuminated, and there was no impact to the vehicle to cause the air bags to deploy. The vehicle was taken to a local independent mechanic, where it remained for further investigation. The local dealer was not contacted. The vehicle was not diagnosed or repaired. The manufacturer was not made aware of the failure. The failure mileage was approximately 80,000.
The transmission would purge forward when shifting gears. The shifting was very rough. This vehicle had recently been in accident.
Other / unspecified
Reports whose component NHTSA recorded as unknown, or that do not map to one of the categories above.
From owner reports, verbatim
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.
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…
Too few reports in this category for a page of its own — they appear in the full complaint list.
Visibility
Reports naming windshields, glass, wipers, defrosters and mirrors.
From owner reports, verbatim
The contact owns a 2018 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the air conditioning system became inoperable. There was no warning light illuminated. The contact stated that the air conditioning system failed to function properly. The vehicle was taken to an independent mechanic, where it was diagnosed, and determined that the air conditioning condenser had failed and needed to be replaced. The vehicle was not repaired. The dealer was not contacted. The vehicle was not diagnosed or repaired. The manufacturer was not made aware of the failure. The failure mileage was not available.
The contact owns a 2018 GMC Sierra 1500. The contact stated while driving approximately 35 MPH with the rear window defroster activated, there was a burning rubber odor inside the cabin of the vehicle and there was smoke coming from the rear window area. While inspecting the rear window the contact discovered that the rear window connector cover had melted, and the wire connections were a burning amber color, but no flames were present. After disconnecting the electrical connections, approximately 30 seconds later the rear glass panel on the passenger side suddenly shattered. No injuries were reported. The contact’s young daughter was seated in the rear during the failure. The vehicle was taken to the local dealer, but the cause of the failure was not yet determined. The manufacturer was not notified of the failure. The failure mileage was 60,952.
Too few reports in this category for a page of its own — they appear in the full complaint list.
Body & structure
Reports naming the vehicle structure, frame, body panels, doors, hood and trim.
From owner reports, verbatim
Paint flaking top above windshield within one year of ownership! Paint flaking on left rear door within last month!
I LEFT HOME TO GO TO THE STORE. WHILE DRIVING ON THE HIGHWAY MY SUNROOF EXPLODED. THERE WERE NO CARS OR TRUCK IN FRONT OF ME OR PASSING ME. NOTHING HIT MY TRUCK. IT SOUNDED LIKE A SHOTGUN GOING OFF INSIDE THE TRUCK. THE SUNROOF EXPLODED SENDING GLASS EVERYWHERE. I WAS DRIVING ON A 5 LANE HIGHWAY, IT WAS RAINING, BUT NOT A BAD STORM. THE ROAD WAS STRAIGHT AND IN GOOD CONDITION. IT HAPPENED SO FAST I DID NOT KNOW WHAT WAS GOING ON. I PULLED INTO A GAS STATION TO CHECK MY TRUCK. I FOUND GLASS ALL IN THE BED OF THE TRUCK AND MOST OF THE SUNROOF GONE. I HAVE TAKEN IT TO THE DEALER AS THE TRUCK IS UNDER WARRANTY. I WAS TOLD THE WARRANTY DOES NOT COVER DAMAGE AND SO FAR NO ANSWER IT THEY WILL COVER IT. I HAVE HAD THE TRUCK FOR ALMOST 3 YEARS AND IT IS NEARING THE END OF THE WARRANTY.
Too few reports in this category for a page of its own — they appear in the full complaint list.
Seat belts
Reports naming seat belts, buckles, retractors and pretensioners.
From owner reports, verbatim
THE FRONT PASSENGER SIDE SEAT BELT RETRACTOR IS FAILING TO RETRACT. I HAD A PASSENGER IN THE VEHICLE AND AS WE CAME TO A STOP IN MY DRIVEWAY TO EXIT THE VEHICLE SHE UNHOOKED (RELEASED) THE SEATBELT AND IT WILL NOT RETRACT. THE SEATBELT IS NOW CURRENTLY EXTENDED OUT AND WILL NOT RETRACT BACK INTO THE RETRACTOR. I PURCHASED THE VEHICLE TODAY 08-05-2026, I CALLED THE DEALER I PURCHASED IT FROM AND THEY STATE THAT THERE IS NO RECALL ON THE VEHICLE WITH THIS ISSUE. I DID LOOK THE ISSUE UP ON GOOGLE AND INFACT IS STATES A PROBLEM WITH THE SEATBELT RETRACTOR FOR MY VEHICLE. I SENT THEM A SCREENSHOT OF THE CONFIRMATION FOUND AND THEY DECLINE TO ACKNOWLEDGE A REPAIR STATING THERE IS NO RECALL. I WAS ABLE TO MANUALLY FEED THE BELT BACK INTO THE RETRACTOR, IT WAS EXTREMELY DIFFICULT BUT I SAT IN THE SEAT TO DUPLICATE THE ISSUE AND IT WILL DUPLICATE. THE SEATBELT IS CURRENTLY EXTENDED AND WILL NOT RETRACT AUTOMATICALLY. THE SHOULDER STAP WILL NOT FIT SECURELY AROUND A PASSENGER AT THIS TIME. I HAVE HAD NO PRIOR USE OF THE VEHICLE UNTIL TODAY AS I PURCHASED IT FROM A REPUTABLE DEALER WHO STATES THEY DID A FULL INSPECTION OF IT PRIOR TO SELLING BUT APPARENTLY THIS ISSUE WAS NOT REPAIRED PRIOR TO SELLING IT.
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.
Too few reports in this category for a page of its own — they appear in the full complaint list.
Tires & wheels
Reports naming tires, wheels, hubs, or the tire-pressure monitoring system.
From owner reports, verbatim
Purchased the tires on 10-25-2021 and with only 16,000 miles on the 4 new tires; we have non-normal cracking on the side of the Thread. These tires are only 3 years old. P275/55r20 We are contacting the tire manufacturer and also the tire service center for help under the 60,000 mile warranty. Bridgestone Dueler A/T Revo 3. The tires should not be cracking for any reason and should not be cracking due to dry rot or stress on the tire. Used on a 2018 GMC 1500 Serria.
In May 2022, I purchased four Cooper Discoverer A/T All-Season 117T 275/55/R20 tires from Walmart.com for my 2018 GMC Sierra 1500 SLT. In May 2023 my vehicle developed a vibration when driving at certain speeds, so I took it to a GMC dealer for a tire rotation and balance. The mechanic discovered that one of the tires had a large bubble on the inner sidewall. He considered it such a safety risk that he insisted on removing the tire and replacing it with the spare before he would let me drive home. The tire was replaced with another of the same kind and tread depth. Yesterday (September 28 2023) I felt that my truck was wandering and swaying. I made an appointment for it to be inspected on Monday, and planned not to drive it until then. Today I observed that the rear passenger tire appeared low. I was shocked to find a split in the inner sidewall approximately one third of the circumference of the tire. I also found a large bubble on the inner sidewall of the driver's side front tire. I am shaken that I could have had three different tires blow out potentially killing myself and other motorists. I will be retaining the tires for inspection, and photographs have been taken. The manufacturer has been contacted. It seems that other model tires have been recalled by Cooper for the same issue, but I have not found a recall for this specific tire.
Too few reports in this category for a page of its own — they appear in the full complaint list.
Exterior lighting
Reports naming headlights, tail lights, turn signals and other exterior lighting.
From owner reports, verbatim
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).
PASSENGER SIDE HEADLIGHT JIGGLES UP AND DOWN CONSTANTLY OVER EVERY SMALL BUMP. VERY DISTRACTING AND LEAVES MANY BLACK AREAS ON THE ROAD FROM LACK OF LIGHT. FIX THIS IMMEDIATELY!
Too few reports in this category for a page of its own — they appear in the full complaint list.
Transmission
Reports naming the automatic or manual transmission, including shifting behaviour, shudder, slipping and transmission control modules.
From owner reports, verbatim
The contact owns a 2018 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the transmission vibrated. No warning lights were illuminated. The vehicle was taken to an independent mechanic, where it was diagnosed with a failing torque converter. The contact was informed that the torque converter needed to be replaced. The vehicle was not repaired. In addition, the contact was informed of a Manufacturer's warranty. The contact was informed of a Manufacturer's warranty for the 2018 GMC vehicle's transmission failure due to the incorrect oil being used during production of the torque converter. The dealer was made aware of the failure; however, the contact was informed that the manufacturer needed to approve the repair coverage. The manufacturer was made aware of the failure but provided no assistance. The contact was advised to contact the NHTSA Hotline to report the failure. The failure mileage was approximately 89,000.
The contact owns a 2018 GMC Sierra 1500. The contact stated that while driving at 45 MPH, the vehicle began to shudder, and he decreased the speed. The contact drove to his residence. The next day the vehicle was driving as expected until it became hot and began to shudder again. The transmission was not shifting as designed. The contact checked underneath the vehicle but failed to locate an issue with the transmission. The rear differential was hot and burned his fingers, but medical attention was not provided. The vehicle was taken to the local dealer, where it was diagnosed that the torque converter and transmission needed to be replaced. The vehicle was not repaired. The manufacturer was contacted, but no additional assistance was provided. The failure mileage was approximately 22,000.
Too few reports in this category for a page of its own — they appear in the full complaint list.
Interior & seats
Reports naming seats, latches, locks, linkages and interior fittings.
From owner reports, verbatim
I purchased a 2018 GMC Sierra 1500 6.2 Denali new. I followed all service requirements including oil changes by GM dealerships. 2025 i noticed my truck power was decreasing. Than I started to hear knocking noses. I took it to a dealership for diagnosis but they couldn't identify anything. Finally it started to skip this is when a dealership diagnose it as being an issue with the active fuel management system. They said my lifters, camshaft, and various other parts was damaged and had to be replaced. Additionally, they said it was a recall on 6.2 engines with the same identical issue but my year wasn't included. The cost to repair approximately 10,000. I really need your attention to this matter! September 10, 2025 my truck placed me and others in danger when it lose engine power. Also my engine light was on for the first time.
TL* THE CONTACT OWNS A 2018 GMC SIERRA 1500. THE CONTACT STATED THAT THE DRIVER'S SEAT MADE POPPING NOISES AND MOVED FROM SIDE TO SIDE WHILE THE VEHICLE MADE TURNS. THE MANUFACTURER ISSUED AN UNKNOWN TECHNICAL SERVICE BULLETIN, BUT IT WAS NOT COVERED UNDER A WARRANTY. THE VEHICLE WAS TAKEN TO COLONIAL BUICK GMC (3965 ATLANTA HWY, LOGANVILLE, GA 30052, (678) 922-9606), BUT THEY REFUSED TO INSPECT THE CONDITION OF THE SEAT. THE DEALER ALSO REFUSED TO NOTIFY THE MANUFACTURER. THE DEALER ACKNOWLEDGED THE SERVICE BULLETIN, BUT CLAIMED THAT THEY COULD NOT DUPLICATE THE FAILURE. THE MANUFACTURER WAS NOT CONTACTED. THE VEHICLE WAS NOT DIAGNOSED OR REPAIRED. THE FAILURE MILEAGE WAS 28,000.
Too few reports in this category for a page of its own — they appear in the full complaint list.
Heating & air conditioning
Reports naming the heating, ventilation and air-conditioning system.
From owner reports, verbatim
TL* THE CONTACT OWNS A 2018 GMC SIERRA 1500. THE CONTACT STATED THAT THE AIR CONDITIONER DID NOT COOL WITHOUT WARNING. THE VEHICLE WAS TAKEN TO THE KING CADILLAC DEALER, LOCATED AT: 1700 W EVANS ST, FLORENCE, SC 29501 WHERE IT WAS DIAGNOSED THAT THE CONDENSER NEEDED TO BE REPLACED. THE MANUFACTURER WAS NOT MADE AWARE OF THE FAILURE. THE VEHICLE WAS NOT REPAIRED. THE FAILURE MILEAGE WAS 50,000.
Too few reports in this category for a page of its own — they appear in the full complaint list.
Higher-selling and older vehicles accumulate more reports. Counts are not failure rates and are not directly comparable between vehicles that sold in very different numbers.
Elsewhere on this vehicle
Data sources
- NHTSA Office of Defects Investigation — owner-reported complaints and the components recorded on them
Data on this page last refreshed .