2018 GMC Sierra 1500 complaints

The embedded navigation system in my 2018 GMC Sierra is no longer supported. Paid map updates were available until 2023, when General Motors discontinued them without notice. This system was marketed as a core feature and provided offline GPS guidance independent of cell reception. I discovered the change while attempting to purchase an update and was told there are no remaining copies and that no further updates will ever be made. I was never notified. When I contacted support, I was transferred through six departments. One representative admitted that customers were supposed to be informed but were not. She stated they are trained to say “there’s nothing we can do” and acknowledged receiving hundreds of similar complaints. She also confirmed the final map update existed but was allowed to sell out. This puts safety at risk, particularly for drivers in rural areas, areas with poor cell service, or while towing. The system is not CarPlay-based and does not rely on mobile data. It was the only in-vehicle routing system many drivers depended on during travel, including emergencies. Its quiet discontinuation means drivers no longer have access to accurate, integrated navigation—reducing their ability to safely plan or adjust routes while on the road. The failure to maintain this system or provide reasonable access to the final update undermines long-term vehicle safety and owner trust. General Motors has not offered an inspection, recovery, or remedy.

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 while his mother was driving 75 MPH on the highway, there was a popping and ticking sound coming from the engine, and while depressing the accelerator pedal the vehicle failed to respond. The driver was able to pull over to the right side of the road and waited for tow truck assistance. A dealer was not contacted. The vehicle was towed the dealer and was diagnosed and determined that the engine needed to be replaced. The vehicle was repaired. The manufacturer was notified of the failure, and informed the contact engine would take a while to be ordered. The contact was referred to the NHTSA Hotline for assistance. The failure mileage was 58,000.

I'm experiencing constant transmission shuddering at constant speed between 25 and 40 mph. This is a know issue, General Motors known issue, with the 8 speed transmission installed in this vehicle. TSB 18-NA-355 was issued in August of 2019 for this issue, but general motors refuses to recall all affected vehicles. Something needs to be done about this!

This 2018 GMC Sierra has 100,000 miles on it and in April 2025 the transmission went out and needed a new one. Now in July 2025 the engine has lifter failure leading to the need of a new engine.

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.

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!

When driving the transmission will shift hard almost jumping forward, especially from a stopped position into 1st.

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.

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.

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.

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.

Lifter when bad during engine start up. (known issue)

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.

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.

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.

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.

The transmission would purge forward when shifting gears. The shifting was very rough. This vehicle had recently been in accident.

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.

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.

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.

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

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.

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.

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.

Lifters failed and damaged engine at 68000 miles

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.

Transmission malfunctioned while driving, causing no available power to move the vehicle. Had to coast in neutral and stopped in the road. Towed the truck to the dealer and they confirmed the transmission has failed. No warning lamps present or pre-indication of failure.

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 assum

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.

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.

Vehicle jumps when shifting gears. When coming to a stop it jumps Forward. Hard shifting.

Knocking, stalling, shaking, lost of power and steering problems. Serviced transmission twice and I was advised to serve every 30000 miles!!! I owned several types of vehicles but I never heard such things before. Technician told me that apparently many GMC customers reported same problems.

Lifters and cams fatal failure, requiring extremely pricy replacement of the parts affected or replacement of the entire engine!

My 2018 Silverado 1500 has had 3 cylinder 4 misfires over a 9 month period that had to be repaired after warranty. This caused the repair/replacement of the lifters. I have had this happen for a forth time this year January 7 2025 with the same code of "cylinder 4 misfire". That means four of the same issues in one year. I can be driving along smoothly, then suddenly from one light to the next, the check engine light comes on with the misfire to cylinder 4 coming on. It was shared with me the AFM can cause this to happen. On the third time of misfire, I saw a little smoke, then once it was repaired with lifters replaced, no smoke and back to running smoothly. This time the intake cam lobe was scored which voided the warranty. I am now at a crossroad as to what to do now, and have parked the truck for now. It is my understanding the 5.3L engine was considered a solid engine until the AFM was installed. Did I mention this is the first "truck" I have ever owned? I have had a Chevrolet vehicle since I was able to drive, and have never had engine problems of this magnitude. My concern now is that this could cause my engine to lock up while I'm driving around and cause a possible accident. I depend on this truck as my mode of transportation, but now I have to make a decision that impacts me greatly as a senior citizen on a fixed income.

The failure was a lifter collapsed in my vehicle's motor. I had reduced power and major shuttering due to the issue. If I had been towing a load I would have possibly become a hazard by not maintaining a speed that would have been able to keep up with traffic flow. Also if I had been in an congested traffic area I would have been slower to clear or have major breakdown causing increased backups. It was confirmed by a local shop. There were no warning lights at the time of incident, nor leading up to this incident. Fortunately no accidents or disruptions happened and I had to be towed in to a repair shop.

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.

The contact owns a 2018 GMC Sierra 1500. The contact stated that while driving on the highway at various speeds, the vehicle occasionally shuts off. The contact stated that several unknown warning lights were illuminated. The contact stated that the vehicle was pulled over to the side of the road and restarted. The contact was able to continue driving. The vehicle was taken to a local dealer and was diagnosed; however, the cause of the failure was not found. The contact was informed to take the vehicle back to the dealer if the failure returned. The manufacturer was notified of the failure. The approximate failure mileage was 128,000.

Electrical system turns off power steering while driving Dashboard lights up like a Christmas tree service track service brake stability Had this service back in 2022 August the problems have resurfaced there are no recalls have spent lots of money and still failing Spent almost a year at the dealership fast forward to years later the same problem is occurring I am running out of money

Engine failed before 100,000 miles. Lifter failed leading to a damaged camshaft and replacement of lifters being require. Required 10,000$ in repairs. Failure light appeared suddenly. No issues were known of ahead of incident.

When accelerating (at times) truck will shudder. Sometimes barely noticeable, sometimes violently. Was told by dealership that torque converter is going out and will be $4000 to replace but may not even fix issue. Looking online, appears that MANY (1,000’s) people are having same issue and that there is even a class action lawsuit about this issue. But no investigation by NHSTA yet, even though I can see many many complaints of similar issues

Shaking when accelerating. Sometimes so extreme it feels like you have been hit by another car. Random, inconsistent, and comes out of nowhere

The contact owns a 2018 GMC Sierra 1500. The contact stated while driving at an undisclosed speed, the engine temperature rose to 210 degrees and the vehicle started jerking. The contact stated that the failure also occurred while idling for a while, or while stopped at a traffic light while refueling, and before accelerating. The failure occurred once the engine temperature rose to 210 degrees. There were no warning lights illuminated. The vehicle was taken to a certified mechanic at a transmission shop who confirmed there was a failure with the transmission; however, the mechanic was unable to determine the cause of the failure. The dealer was contacted; however, the vehicle was not diagnosed or repaired. The manufacturer was not made aware of the failure. The failure mileage was 117,000.

This vehicle has 88400 miles, it out of warranty, which I know this, I use AMSOIL ASM SIG SERIES SYN SAE 0W-20 , 5.3L GAS. TWO YEARS AGO, I CHANGED OIL AT RICHARD BUICK GMC IN DAYTON, OH AND SENT A SAMPLE OF THE OIL TO OIL ANALYZERS FOR AN ANALYSIS, THEY SET IT BACK, IT SHOWED THERE WAS A LEVEL 4 SEVERE GASOLINE IN THE OIL. THEY CHANGED THE HIGH SPEEP FULE PUMP, BOTH IN JECTORS, AND IT THOUGHT IT WAS FIXED, ON 12 - 11 -24 HAD THE OIL CHANGED AT LOCAL BOYS SERVICE CENTER, SENT A SAMPLE OF THE OIL-TO-OIL ANALYZERS AND RECIEVED BACK, A SEVERE FUEL LEAK OF GASOLINE IN THE OIL, i DON'T THINK THAT MANY DRIVERS WHO HAVE THIS VEHICLE KNOW ABOUT THIS DANGEROUS PROBLEM, IT COULD CAUSE AN ENGINE FAILURE OR EVEN WORSE, GENERAL MOTORS NEEDS TO FIX THIS PERBLEM.

Vehicle is a 2018 GMC Sierra Crewcab 4x4 with a 5.3 engine. The vehicle was purchased new in Washington and serviced at the Chevrolet dealership in Oregon within vehicle recommended service intervals. At 64K miles, the engine developed a sudden AFM lifter issue. Lifter for cylinder #6 came apart causing the engine to miss, smoke, have excessive oil on the spark plug, and low cylinder PSI (75 compared to others at 200+). Vehicle is just outside of it's 5 yr/60K powertrain warranty. Vehicle is undrivable and will need probable engine replacement due to damage from AFM lifter failure. My mechanic verified the miss, oil on the spark plug, and low PSI. The local Chevy dealership removed the valve cover, inspected, and advised that the lifter came apart. Dealership wants $1200 to pull the head to determine extent of damage and $4-5K to repair valves or $12-14K for engine replacement. GM offers no assistance at this point.

Noted the rear sliding window did not work. Upon further research and investigation found fuse 2 in the drivers side fuse box popped. Replaced the fuse and did not solve the problem. Further investigation found the harness that controls the rear sliding window and other items was sheared (all 3 wires cut in half). The harness is routed from the inside of the center console, through the drivers side hinge (pinch point where it cut the harness, and to the backside of the center console. Spliced the wires and reconnected confirming the fix to the problem. This issue poses a fire hazard. Recommend a recall to reroute the harness or a form of corrugation to better protect the harness and prevent further issues.

Part # 23337305 OEM Towing Control Module failure. replaced with factory part and unit failed within 60 days.

Rear sliding window defogger started smoking, filling the cab with smoke