2018 GMC Sierra 1500

When I first bought my 2018 GMC Sierra with the 8 speed transmission it would shift hard from first to second gear. Then at around 58,000 miles my truck also started to have a vibration coming through the steering wheel around 45-55 mph. I took it to the dealership and they changed the transmission fluid and did a software update. I am now at 80,000 miles and my truck still shifts hard from first to second gear and makes a grinding sound when accelerating sometimes. I am afraid to drive my any long distances for fear of the transmission malfunctioning. I have not been back to the dealership since my truck is no longer under warranty. So the problem has not been reconfirmed by a dealer or independent service center or inspected by the manufacturer. There have been no warning lamps or messages or other symptoms. I hope that GM is held accountable for putting a faulty 8 speed transmission in my truck.

DRIVING 70 MPH ON [XXX] IN MODERATE TRAFFIC WHEN MY VEHICLE SUDDENLY SLOWED DRAMATICALLY AND BEGAN TO SHUDDER . I WAS IN THE MIDDLE LANE OF THREE WESTBOUND MARKED LANES AND WAS ALMOST HIT BY A DRIVER BEHIND ME WHICH HAD BEEN FOLLOWING TOO CLOSELY. THE CHECK ENGINE AND TRACTION CONTROL LIGHT CAME ON AND MY OIL GAUGE WENT TO THE HIGH SIDE. I EXITED ONTO [XXX] AND AT 40 MPH THE TRUCK WOULD SHAKE AND SHUDDER UNTIL I DROVE THE 6 MILES TO MY RESIDENCE. ON [XXX], I HAD THE VEHICLE TOWED TO LASH GMC DEALERSHIP IN JOHNSTOWN OHIO. ONCE THERE THE VEHICLE WAS DIAGNOSED WITH A FAILED LIFTER THAT BROKE INTO PIECES RESULTING IN A BENT ROD AND DAMAGED CAM SHAFT. THE DEALER RECOMMENDED FULL ENGINE REPLACEMENT DUE THE SEVERITY OF THE FAILURE. THE TRUCK IS A 2018 GMC SIERRA DENALI WITH ONLY 65,449 MILES ON IT. IT COST ALMOST $70,000.00 NEW AND THE REPLACEMENT ENGINE COST ME $14,221.96. I FEEL MY PERSONAL SAFETY WAS JEOPARDIZED IN THIS INCIDENT. SINCE THAT TIME I HAVE RESEARCHED THE 6.2 GMC ENGINE ONLINE AND HAVE FOUND REPORTS OF NUMEROUS SIMILIAR FAILURES AND INCIDENTS INVOLVING THE ENGINE IN QUESTION. I TRULY FEEL NHTSA SHOULD TAKE A STRONG LOOK AT THE ENGINE FAILURES INVOLVING THIS ENGINE AND FORCE GMC TO REPAIR OR REPLACE THE ENGINES IN QUESTION DUE TO THE SAFETY ISSUES INVOLVING THE ENGINES FAILURES IN TRAFFIC AND THE RISK ASSOCIATED WITH AN OCCURENCE. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

My starter quit at 81,000 miles. It has always been a bit weak starting, but I have never had a starter go out on a vehicle at 81,000. I have replaced it, and the rebuilt starter is better than what was ever on this vehicle. I am also having problems with the transmission shuddering, shifting rough in low gear, and sometimes it reverses fast. Repair shops won't even touch the transmission. The dealership stated they couldn't get the problem to replicate the issues even though they know there are issues with the 8 speed transmissions.

On February 10, 2025 the vehicle, a 2018 GMC Sierra, caught on fire while parked in the driveway of my home. The vehicle had last been driven earlier in the day with a return to home at approximately 12:45pm. At approximately 7pm I heard a loud pop outside of my home and saw orange light coming through the front windows. Upon going outside, I found the rear of the vehicle engulfed in flames. The fire was coming out around the remains of the license plate, up and around the rear bumper on the left side, and progressing up the tailgate and window hatch on the bed cap. The fire progressed forward over the next few minutes as the fiberglass cap burned. Eventually the fire penetrated the front window of the cap and rear window of the cab and began burning the interior of the cab. About the time the fire department arrived the fuel tank ruptured and began spilling gasoline onto the ground beneath the vehicle. The fuel tank was approximately 7/8 full. The fire department eventually extinguished the fire, but the vehicle was a total loss. My wife and I had been in close vicinity of the vehicle during the afternoon hours and had noticed nothing unusual. There had been no unusual issues with the vehicle during the prior drive, which had been a 5 minute drive to/from a local home supply store. There was collateral damage to the front of my house as a result of the heat from the fire, as well as damage to the driveway. If the vehicle had been parked in the garage it is resonable to assume that the house would have been destroyed.

I noticed there was an issue regarding the break assist system in my vehicle a few months ago when I went to go for a drive. It is available to be inspected. The issue regarding safety revolves around the difficulty to break. The low amount of brake availability is dangerous in the case of a situation that if I needed to break quickly it is extremely difficult to. I have not had a certified individual confirm the issue at this time. It has not been inspected. The warning message "Break Assist" comes up every time I try to utilize the brakes. I know there are previous recalls, although when I have tried to see if my truck falls under those recalls it does not.

I have a 2018 GMC Sierra 1500 with a 6.2 motor. Back in December of 2024, I had to replace a tie rod, cam shaft, and the lifters. $8400 to get everything replaced. Since my warranty had expired, I had to pay all of this out of pocket. I know there is currently an investigation going on in GMC's 6.2 motors. Almost 900,000 engine failures. This is unacceptable. GMC just needs to man up and send out the recall notice. Since I have already had to pay for my replacements, GMC should do the right thing and and cut me a check.