Power Train Problems of GMC Sierra 1500 - part 2

While driving the vehicle I received dash warnings of temperature rise. Pulled over and saw a large coolant leak coming from right side of engine compartment. Towed to dealership. Dealership informed me that coolant hose coming from heater core was routed by the manufacturer so that it rubbed on the frame. Dealer indicated problem persists on all vehicles and no given, other than replacing the hose and not remedy the problem. New hose will be in contact with frame again, causing inevitable where and breakage. Dealer did not cover under warranty nor did they offer solution for repair other than replacing those hose.

See all problems of the 2023 GMC Sierra 1500 🔎.

Truck broke down with a rear-wheel lockup and had the transmission replaced in June 2025. In December 2025 and February 2026, truck lost power two times and entered limp mode while on a major highway and major interstate. The problem was misdiagnosed in June 2025, diagnosed properly in December 2025, but not properly repaired, and diagnosed properly in February 2026. All three times the vehicle had this issue, two of the same exact dtcs were present. This is a safety defect, and I have lost all confidence that the vehicle is reliable enough and safe enough for myself and my family.

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Vehicle stalled in busy intersection in mckinney texas , unable to start are shift into a neutral position on transmission to remove from extreme dangerous intersection, sheriff advised that road side assistance that was contacted is not going to be in time (90min)to keep from causing an ongoing traffic backup , sheriff dispatched their own towing service to resolve the situation from getting extremely dangerous . Vehicle and my wife was towed to mckinney Buick GMC dealership.

Hi, was driving vehicle GMC 1500 denali, vehicle lost power, all lites lite up on dashboard, vehicle just lost power and I swerved off road and sideswiped a plant holder on side of road, damaging side passenger rear door. I bought the truck to GMC rvc and they said vehicle blew cam shaft and lifters. I explained to them I'm very concerned for others safety in these vehicles with the 6. 2 engine. Someone is going to get killed or even a family. I did look up this vehicle its not listed in recall, but this vehicle has same engine as ones in recall. Rvc GMC issued me a bill for repairs for the amount of $8185. 20 and they stated they took 3k off invoice. I did pay total invoice. . . . I'm just asking you to please look into this as this is defiantly an issue and this year should be listed on recall as well. . Thanku for at least looking at this. My cell is [xxx] if you need to reach us. . . Thx. . . . Information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).

My vehicles transmission is part of a recall but my VIN is not registered for this recall repair. Please assist.

See all problems of the 2021 GMC Sierra 1500 🔎.

I was driving on the highway with the cruise control engaged. An instruction came on the information center telling me to push the start button, while I was driving at highway speeds. Then the transmission downshifted numerous times violently the last few times. By the tachometer the engine was doing 6000 rpm. I pulled over and the start button would not shut down the engine until about the third time I pushed it. Then it would not restart. I had the vehicle towed to the dealership and they told me that they had gotten the truck to start but that the engine seized while pulling it into the repair bay. I had followed the recall directions that they had sent me for the recall on the 6. 2 liter and they said that mine was fine and that I should use thicker oil from now on. I had done that but still had ths failure, which as a person that has worked on mechanical equipment my whole life, this failure is violent.

See all problems of the 2024 GMC Sierra 1500 🔎.

Transmission shuttering which was confirmed from from GMC dealership , but refused to do any repairs after confirmation or diagnostic and test driving. Demanded a 220$ fee be paid before releasing my vehicle back. Also gave GMC bulliten # 25-na-148 which states the same issues I'm currently having.

I have had shuddering on the highway and a few hard random diwnshifts. Last week I went to start my truck and the transmission started grinding and rattling. I was told after towing to the dealer it needed a transmission due to pump not getting enough fluid and had failed. I was told I needed to pay, even though the part causing the problem had a extended 150,000 miles and the subsequent pump failure is a result of the control valve failure.

Transmission started hash shifting and at highway speed it felt like the dark converter kept falling out of lock up. Stopped and took picture of service light.

This is separate for VIN 3gtuudel5ng657492 I had to change dealerships because beck & masten south / GMC would not provide me with a loaner after being told I was on the list and I was next in line. I waited a month and drove to them and spoke with the girl who oversaw loaners. I explained I had severe safety issues such as front-end wobble which is related to transmission issues. And the oil consumption issue and oil light. Once again, I was re-assured the loaner program was indeed still active and I would be put on priority. Again to no avail I had wasted too much time with beck & masten. After months of this I found out I did not have to take it to the dealer I bought it from. So, I took it to monument Chevrolet. I explained my concerns related to the front-end wobble which was very intermittent. And the oil consumption issue which I was very concerned with due to the year model and mileage of the truck. Also, the 75,000. 00 price tag was really has me extremely upset. . . Monument Chevrolet treated me well. I had actually brought it in and called about the steering which was greatly affected by the severe front end wobble more than one time. I was told at first the oil consumption was pretty normal. Until I told them how much I had to add between changes. I have attached two work orders to this complaint. These work orders show what was done at 18017 miles and 18323 miles. The later work order was when the pico test was done. Also, an oil consumption test was started once I picked the truck up. After I had driven it for 2077 miles and was bringing the vehicle back to monument Chevrolet, as instructed for the oil consumption results, when a loud squeeling, then hard knock, power loss and I pulled over. I called monument and was instructed if I could get it to start and bring it. I drove it to them while knocking and rough running. It has been in the shop for over 2 months for an engine replacement. 2077 miles after recall work! refer complaint 11729716.

See all problems of the 2022 GMC Sierra 1500 🔎.

I was driving on a highway on my way home from work. Thank god there was not a lot of traffic because my truck just shut off lost all power, then I received a message on the dash to put on neutral and restart. I tried multiple times to turn it back on. It never turned on and had to get it towed to nearest dealership. It took them a week to inform that the engine locked up even though I tried to take it for the recall they told me to wait and reschedule the appointment. Never got a new appointment until the engine failed and I got it towed to the dealership and have also not received a new kind of loaner from gm. This will be my last GMC truck I purchase.

The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving approximately 45 mph, the transmission inadvertently shifted from drive (d) to first gear. The check engine warning light was illuminated. The vehicle was pulled over to the side of the road and then towed to the dealer, where it was diagnosed, and it was determined that the valve body needed to be replaced. The vehicle was not repaired because parts were not available. The manufacturer was notified of the failure. The failure mileage was approximately 103,000.

Drastically reduced power on highway resulting in reduced acceleration due to code p0198 engine coolant control valve position sensor. Required me to drive at reduced speed on highway to get to dealer. Safety issue.

My 2026 GMC at4 3. 0l duramax had a catastrophic engine failure on Sunday, February 8, 2026. It went into reduced acceleration and also fault code po6dd. Thankfully I was not on a highway. The truck would not run over 45 mph on flat ground, and then by the time I got it to a safe location 5 miles away it would not run over about 30mph. This obviously resulted in the truck being towed to a dealership. I have been told the entire engine will be replaced. Upon further reading, I suspect this is a thrust bearing failure that is a well-known issue in this lz0 duramax engine. What I have read, this issue is occurring mostly on trucks built from may-sept 2025, and my truck has a 7/2025 build date. This could have been major safety hazard if the engine had failed in a major freeway/highway.

I’ve gone through two transmissions on my 2018 GMC Sierra 1500 both times the same issue. The gears are shot, hard shifting. Vehicle is well maintained. Both transmissions one original equipment and second bought at the dealership the truck was bought both only lasted over 80000 miles. Driving the truck loss of power or torque is noticed, then a hard shifting. Checked fluid all was good not seeing metallic shavings. Then the overheating of the transmission, faulty valve replaced with aftermarket bypass and did transmission flush. But each occasion there was an incident I would’ve driving on the interstate and vehicle would lose power and almost hard stop and cause a crash. Then vehicle would only go in reverse both times the transmission gave out. The only warning light that ever came on was a transmission overheating and nothing else. I’m currently in the process of having to get another transmission because of the same issue again. Vehicle was seen by a technician and deemed the transmission was shot again.

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The contact owns a 2024 GMC Sierra 1500. The contact stated that while driving at 67 mph, the transmission shifted to neutral(n) unexpectedly. In addition, the vehicle failed to accelerate as intended while depressing the accelerator pedal. The contact attempted to drive the vehicle off the road. A passerby slowed down and allowed the contact to move over to the side of the road. The engine seized, and the vehicle stalled between the shoulder and the line of the left lane. The check engine warning light illuminated, and the messages "battery low" and "reducing features to save battery" were displayed on the instrument panel. The contact called a friend who towed the vehicle to the dealer. The dealer was informed that the engine had failed and needed to be replaced. The vehicle remained at the dealer unrepaired. The contact stated that due to the failure, the contact no longer felt safe while driving the vehicle. The manufacturer was notified of the failure. The failure mileage was 52,680.

On 2/4/2026, my vehicle (2019 GMC sierra at4 and VIN # 3gtp9eed5kg240494) experienced a catastrophic failure of the engine oil cooler lines. This is a well-documented manufacturing defect involving the failure of the crimp joints between the rubber hose and metal tubing. This failure occurred abruptly, causing massive oil loss and posing a severe safety risk due to the potential for sudden loss of oil pressure and engine seizure while operating the vehicle at highway speeds. This specific component failure is recognized by general motors under customer satisfaction program (csp) n212326940. Gm explicitly acknowledged this failure as a manufacturing defect. Despite the fact that the defect is inherent to the part’s design—and not a result of typical "wear and tear"—gm has denied my request for reimbursement, citing that the vehicle is outside the standard 36,000-mile warranty period. I exhausted all good-faith efforts to resolve this through GMC’s internal escalation process. I spoke with a representative and a supervisor, both of whom refused to honor a reimbursement request based on the manufacturing defect. They refused to consider that the defect, as documented in gm’s own internal bulletins, is independent of mileage and that the repair was performed at an authorized gm dealership. I am seeking full reimbursement of $2,171. 58 for the repair of a known, safety-related manufacturing defect. Gm is failing to stand behind their "professional grade" standards by refusing to cover a part they have already admitted is defective. I request that your office mediate this dispute to facilitate a full refund of my out-of-pocket repair costs.

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Incident summary: on 2/2/2026, my vehicle was serviced under safety recall 25v-274 at an authorized GMC dealership. The service technician performed the mandated diagnostic protocol (including the picoscope test) and informed me that the engine had "passed" inspection. No internal components were replaced; the remedy was limited to an oil change to a higher-viscosity oil (0w-40) and a new oil filler cap. The failure: approximately 48 hours after this "successful" recall remedy, the vehicle suffered a catastrophic engine failure while in operation. The engine failed entirely. The vehicle lost all propulsion while in motion, creating an immediate safety hazard for myself and other motorists. Diagnostic and risk: the failure has been confirmed by a GMC dealer, who subsequently performed a full engine and radiator replacement. In the 48-hour prior to failure, there were no warning lamps or symptoms; the vehicle had just been cleared by the manufacturer's own diagnostic tools as safe and free of defects. Systemic concern: this incident demonstrates that the current diagnostic protocol for recall 25v-274 is insufficient to identify terminal manufacturing defects in the connecting rods and crankshaft of the l87 6. 2l v8 engine. The "remedy" of higher-viscosity oil failed to prevent the exact catastrophic loss of propulsion the recall was intended to address. The replaced engine is available for inspection upon request by the NHTSA office of defects investigation.

I've been to the dealership a few times due to the truck jerking violently under very light acceleration when its trying to shift gears. Also there was a few times that the rear wheels have locked up while driving.

Vehicle is shifting hard when switching gears. Typical with the recall and the valve body being the issue. Dealership is saying it is not covered by recall.

I am submitting this complaint regarding a recurring transmission issue in my vehicle. The transmission consistently jerks and shifts erratically, particularly in the morning during initial operation when at cruising speeds of about 50-75 mph. This behavior occurs when the transmission temperature is below approximately 100°f and happens on a daily basis. The gear changes feel harsh and abrupt, kind of like it doesn’t know what gear to be in its raising concerns about both drivability and long-term transmission reliability. I brought the vehicle to an authorized dealership for inspection. After evaluating the issue, the dealer informed me that the behavior was due to the vehicle being in “sport mode. ” however, this explanation does not resolve the concern, as the severity and consistency of the jerking appear abnormal and occur regularly under the same temperature conditions. Given the persistent nature of this problem and its potential safety implications — especially during acceleration and low-speed driving — I am requesting that this issue be formally documented and investigated. Thank you for your attention to this matter.

I was driving and the engine abruptly stalled. The truck self-shifted to neutral. Once stopped, I shifted to park to attempt a restart. It would not crank. I was on a 2-lane road so I did not have a shoulder. Once I realized it would not restart I tried to shift to neutral so I could push it to a subdivision road about 50 yards away only to find out my transmission has no ability to shift to neutral (the dealer confirmed this later). So I was stuck on the road for hours just over the crest of a hill with people coming up on me and my family at 50mph. It was a windy 10 degrees so we could not wait on the side of the road where we would have been safer. This is how people get killed; being stopped where people can't see you and do not expect you to be stopped. Why can I not get the truck off the road? if this happened on an 8-lane highway how would I get to a shoulder, even after traffic had stopped behind me? on top of all that, the problem with the truck ended up being an engine bearing failure (per the dealership service dept) that is a known problem with this engine and truck build date. General motors needs to proactively diagnose and get these engines replaced before someone gets hurt. There is a TSB issued for the bearing issue but when I asked my dealer about it a month ago, before the failure, they acted like they knew nothing about it and told me to bring it in if I hear noises. If they had offered to check the crankshaft endplay when I asked about it ( as the TSB suggests), I may not have gotten stranded and my family's safety put at risk. There were no warning lamps, and no strange noises before the engine seized. My fuel economy had decreased by about 20% in the last month but that may be from cold weather operating conditions. I have a separate electrical issue that I've been chasing down and I assumed this stall condition was related to that. But the dealer confirmed this was a bearing failure.

See all problems of the 2025 GMC Sierra 1500 🔎.

On Friday, January 30, 2026 while driving our 2020 GMC Sierra 1500, we experienced sudden loss of power and the motor making a faint rattling noise. The motor soon after began making a horrible sound - - it was obvious something was very wrong. This vehicle only had 31,995 miles on it at the of the issue. We had the truck towed to the dealer the following day for evaluation. Upon inspection, it was determined that the #5 lifter had collapsed and the left bank of lifters needed to be replaced at an estimated cost of $4500. There were no warning lamps or alerts on our app for over 24 hours. Once at the dealer, we explained to the service advisor that our research concluded that gm is fully aware of these issues and that they are under investigation for possible recall. Our service advisor then made a call to gm who agreed to cover this repair under warranty (which we appreciate and feel was the right thing to do). However, after additional research, we are concerned that the right bank of lifters will fail next, or even worse, catastrophic engine failure that gm will refuse to cover. It is our understanding that ntsb is aware of these issues and is in the process of conducting an investigation. I would like to have our issue added to the investigation.

I was driving my 2022 GMC sierra with the 6. 2 engine 10 speed transmission and I was at at a red light, the light turned green and I went to go and I could feel my rear wheels lock up and then it released went into limp mode was not shifting gears correctly and I had no reverse.

Odd noise from bell housing area at 1200 miles that went with engine rpm. Took the truck in to the dealer and they said they couldn't recreate it but to bring it back in if it returned. Jan 27th at 5200 miles on the truck, I was driving down the highway at 60mph and got a reduced acceleration message on the dash along with a check engine light. Brought it to the dealer and was informed it was a bad thrust bearing and needed and engine and turbo replacement. Still waiting for the truck to be done.

Transmission locked up after leaving a stop sign. Rear wheels locked and vehicle was inoperable. Dealership repaired with replacement transmission valve body parts under warranty.

While entering the freeway at approximately 45 mph not towing the rear wheels locked for a second, truck went into the limp mood, and dash said reduce speed, service transmission. Dealer pulled codes, p0700 and p0747. . . The order says cause document #6998510. "replace spacer plate, check balls and valve. " correction: dtc p0747 set dealer told me the put the new updated valve in but I don't see that on the repair order? I asked about the gm extended warranty ( I think it's 10 years, 150,000 miles). They said it didn't apply to my vehicle?.

The def tank in my truck is defective and its the second time in the last 14 months it has broke. The part is now back ordered and according to the dealership this is a nationwide issue regarding these specific trucks. I have contacted around 10 dealers in my area and all tell me the same thing that they have multiple trucks waiting on the same issue. I have not had my truck for over 2 months and have no idea when I will be getting it back due to dealership having no idea when the part will be released due to the back order. This seems to a huge issue with these trucks and gm is doing nothing to help resolve it. I've reached out to gm directly and get no assistance and now have made 2 payments on my truck and the dealership refuses to give me a loaner vehicle. I am looking for some help or relief on what to do to go about my issue.

Vehicle: 2023 GMC [model], black widow package, 6. 2l l87, 41,078 miles recall: 25v?274 / gm [xxx] ; recall remedy performed by marty’s GMC (kingston, MA) on 2025 -11-12; oil changed per recall procedure post?remedy symptom: intermittent knock starting ~01 - 2025 / about two months after remedy incident: Jan 23, 2026 — engine seized / loss of propulsion while driving; stranded on highway off?ramp; vehicle impeding traffic causing dangerous conditions. Codes: obd scan by passerby indicated camshaft position sensor / correlation error (exact code not captured) crash/injuries: none current status: vehicle at marty’s GMC since Jan 23; not diagnosed as of Jan 29; GMC case #88159466 safety concern: sudden loss of motor power in traffic after recall remedy on Friday, Jan 23, 2026, while my daughter was driving, the engine seized / the vehicle lost propulsion and stranded her on a highway off?ramp. The vehicle was impeding traffic and had to be moved. It restarted briefly and was moved to a safer location but still impeding traffic. A motorist scanned the obd port and reported a camshaft position sensor / cam-crank correlation error (exact dtc unknown). No crash occurred and no injuries occurred. The vehicle has been at marty’s GMC since Jan 23, 2026 and as of Jan 29, 2026 it has not yet been diagnosed. I opened a case with GMC customer assistance (case #xxx). This is a safety-related loss-of-propulsion event occurring after the recall remedy was completed. Information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).

The contact owns a 2015 GMC Sierra 1500. The contact stated that while at a complete stop and attempting to shift into reverse(r), drive(d) or park(p), the gear shifter was stuck, and the contact had to go underneath the vehicle to move the shifter cable into the intended gear. The vehicle was taken to an independent mechanic, where the upper and lower shifter cables were replaced. The contact stated that upon returning to the residence and attempting to park the vehicle, the gear shifter failed to remain in the intended gear and was moving unintendedly. The vehicle was not repaired. The dealer and the manufacturer were not contacted. The failure mileage was approximately 225,740.

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On the afternoon of 01/20/26, I was merging onto the highway in my 2021 GMC Sierra 1500 when a loud bang was heard from the engine compartment at approximately 60 mph. Immediately after the ban was heard, several indicator lights on the dashboard were illuminated, including the esc, check engine light, and parking brake light. A power loss was felt when attempting to accelerate and the banging noise worsened anytime the accelerator was depressed. I was able to drive the vehicle to the nearest gm dealership that coincidentally was at the closest exit off of the highway I was traveling on. The dealership performed diagnostic and determined that the damage was caused due to the ongoing gm recall associated with safety recall n252494000. My vehicle had previously been inspected as part of the recall and was found to have passed. Vehicle had been driven approximately 4,000 miles after recall was performed.

4 months after bring my truck back to the dealership for a body valve issue on the 10 speed transmission. The truck went into limp mode while I was driving.

Driving at 35 mph in traffic and the rpms started to increase to 3500rpm and vehicle started to slow down inevitably putting me into reduced acceleration. . Limp mode. Truck would not shift into reverse either once I could safely merge out of traffic and put into park. Very very dangerous and scary situation.

I had the truck inspected for recall n25249400 on August 11, 2025 with 24,610 miles. It passed the recall inspection and the dealer changed the oil to gm recall recommended oil. On January 18, 2026 with 28,275 miles, the engine seized while on a major highway. The truck lost all power and just turned off amd would not start or turn over. The vehicle was towed by the police due to the vehicle being in a dangerous spot in the middle of a lane on the highway whi h I had to pay out of pocket. January 19, 2026, the gm dealer confirmed that the truck needs a new engine due to the recall defect. They said that they had just ordered a new engine, but does olnot know hpw long ot will take to get and then install. The dealer is unable to provide a rental vehicle which means, I can't work!.

While traveling 60 mph on a divided highway went to pass another vehicle. Had no throttle response the engine had completely turned off, locked up seized up. I’m not sure what caused the engine to just lose all power. Had to go back to the lane and luckily there was a turnoff where I was able to turn off the highway.