2020 GMC Sierra 2500 Owner Complaints

The contact owns a 2020 GMC Sierra 2500. The contact stated that the check engine warning light was illuminated, and the message "Reduced Power" was displayed. The vehicle was taken to the dealer, where the turbo actuator and wastegate position sensor A-circuit were replaced; however, the failure persisted. The vehicle was taken back to the dealer, and the contact was advised that another diagnostic test was needed. The contact declined to pay for the diagnostic test. The vehicle was taken to a retired GM mechanic, who diagnosed the vehicle with turbo charger failure. The vehicle was not repaired due to the cost. The manufacturer was notified of the failure, but no assistance was provided. The failure mileage was approximately 100,000.

NHTSA ID

11747347

Incident

May 30, 2025

Mileage

100,000 mi

While driving down a highway doing between 45 and 55 mph the transmission suddenly and completely faulted causing the truck to come to a complete stop. Just enough power to get to the shoulder luckily. The transmission had basically completely blown out, fluid everywhere. The insurance company did not find any comprehensive damage. The entire transmission needs to be replaced. There were no indicators showing any problems, no alerts, no warning whatsoever. Mechanics said there was a lot of metal coming out of the transmission. The truck is currently in a mechanic shop awaiting the new transmission, so at this time it is available for inspection. The safety issue here is that it happened on a busy highway, and the vehicle was no longer drivable so it needed to be towed causing more time spent on the side of the road.

NHTSA ID

11723197

Incident

Feb 18, 2026

A couple times I heard loud clanking coming from rear brakes. One time in particular I was trying to stop and it felt line someone had ran into my truck but must have been the rear wheel locking up

NHTSA ID

11718162

Incident

Jan 30, 2026

The main tailgate will not go down or function properly and it says online there is a national recall for this, but does not come up when I search my vehicle. When I turn on my left turn signal the brights flash for no reason and this is a known major issue with the vehicles as well. The trucks computer is telling me low on coolant even though it is not that has already been fixed through a 3rd pARTY WARRANTY Parking brake was stuck on when I bought the vehicle and had been for a long time you could tell and I had to pay over $1100 to fix it at GM. The Ford collision system does not work properly and the cameras will come on at certain times when they're not supposed to be and not come on when they are supposed to be

NHTSA ID

11706292

Incident

Dec 19, 2025

Bad vibration and bad wobble in steering wheel and front end components. This is the 3rd or 4th time my truck has been back to the dealer because of the same issue!

NHTSA ID

11704835

Incident

Nov 1, 2025

Catastrophic engine failure after taking it in for the April 2025 recall. Complete engine replacement needed

NHTSA ID

11703546

Incident

Nov 26, 2025

The rear defroster massively overheated. It started heavily smoking and eventually exploded the rear windows. Only warning sign was the smoke which we noticed quickly because the windows were up. Had the windows been down we might not have noticed before a fire started. I'm taking it to a dealership now. This module also triggers on from a remote start. Extremely dangerous!!!

NHTSA ID

11701143

Incident

Nov 23, 2025

Torque converter in my transmission we out, causing my gears to grind and lose power. Slight rumbling sound under the front passenger seat, First dealer (Palmen Motors, Kenosha WI) told me there was nothing wrong with the vehicle and no transmission error codes exist. Second dealer (Parks GMC, Greenville SC) indicated that i need a complete new transmission. Part is on backorder for the last 4 weeks and I am without my vehicle. No ETA for new part or any information on why it failed prematurely.

NHTSA ID

11693346

Incident

Jun 13, 2025

I have taken the vehicle to my local dealership six times. The tailgate started opening and the headlights were blinking on and off. This happened 3 months after I bought it. The dealership told me they changed the tailgate switch and they said there wasn’t anything wrong with my lights. Two weeks after the dealership said they changed the tailgate switch, the tailgate started opening and closing. The lights also stopped working driving down the road at night. This happened 3 different times at night. The tailgate opened when I was pulling a trailer and it caved in and I had to pay to have it repaired. The dealership said it wasn’t their problem. During this time the power steering fluid was leaking under my steering wheel and ruined my carpet. The dealership has yet to acknowledge that problem. I still have to put power steering fluid in the truck every week and my interior is ruined. The tailgate is still opening on its own. I had to start charging my batteries up every morning because they were dead. I got up one morning and the batteries were dead and the truck wouldn’t start. I had to buy a new $300 key. Took it back to the dealership for an appointment. The truck sat there for a week and I called for an update and they didn’t even remember the truck was there. It still sat there 4 days after that. They told me the truck needs new batteries and it wasn’t under warranty. I spent $1000 on 2 batteries. Tailgate is still going down. The lights are still going on and off. And then the lights and the locks will go on and off while the truck is parked and turned off. And now the new batteries are becoming weak and I am having to get the truck jumped off several times. I have had the truck at the dealership 6 times and they still haven’t fixed anything. When they have my truck I am losing money because I am a business owner and I use my truck for work. I lost all of my tools. I have lost time and money because the dealer has yet to help and do their job. I need help GM

NHTSA ID

11691983

Incident

Dec 31, 1969

The catalytic converter failed at 93,000 miles, and 64 months. GM says it is out of warranty.

NHTSA ID

11687414

Incident

Jun 11, 2025

The contact owns a 2020 GMC Sierra 2500. The contact stated that while driving approximately 70-80 MPH, the transmission downshifted, and the rear wheels locked up. The contact was able to coast to the side of the road. The contact was unsure if a warning light had illuminated. The vehicle was towed to the dealer, where it was diagnosed and determined that the transmission had failed and needed to be replaced. There were metal shavings found mixed in with the transmission fluid; however, the vehicle remained with the dealer unrepaired. The contact was informed by the dealer that the warranty had expired, and the vehicle could not be repaired. The manufacturer was notified of the failure but declined to assist in covering the cost of the repair. The failure mileage was approximately 166,000.

NHTSA ID

11679851

Incident

Jul 11, 2025

Mileage

166,000 mi

The contact owns a 2020 GMC Sierra 2500. The contact stated that while her husband was driving 30 MPH, the rear wheels locked up and the vehicle skidded to a complete stop. No warning lights were illuminated. The vehicle was towed to the dealer, who diagnosed a failure with the transmission. The contact was informed that the transmission had imploded and needed to be replaced. The vehicle was not repaired. After investigating the failure, the contact related the failure to NHTSA Campaign Number: 24V797000 (Power Train); the VIN was included but the vehicle had not been repaired. The manufacturer was not notified of the failure. The failure mileage was 125,000.

NHTSA ID

11671648

Incident

Jun 28, 2025

Mileage

125,000 mi

What component or system failed or malfunctioned, and is it available for inspection upon request? - Transmission Valve Body resulting in a P0700 & P0747 code. Yes currently installed in vehicle. How was your safety or the safety of others put at risk? - When the vehicle goes into a limp mode to protect the transmission and rear-wheel lock up, the truck shuttered and hard downshifted. Speed limit is restricted to 5th gear only. I've been instructed by GM to continue driving and using the vehicle until the problem happens again, knowingly putting myself and others at risk on a second failure that could happen at any time. Has the problem been reproduced or confirmed by a dealer or independent service center? Yes this is a common problem with a recall #N242454440, NHTSA 24V-797. Has the vehicle or component been inspected by the manufacturer, police, insurance representatives or others? Mine has been rejected by GM. Although I documented and photographed the failure codes, I cleared them from the vehicle in order to attempt to safely get to the dealer and prevent further damages. Were there any warning lamps, messages or other symptoms of the problem prior to the failure, and when did they first appear? At the time of failure yes, check engine light and codes from an engine monitor coinciding with the known problems. Engine speed / power was reduced to allow only 5th gear.

NHTSA ID

11668939

Incident

Jun 20, 2025

After the transmission recall was completed, I’m now having erratic shifting. Having the recall adding software monitoring for a hardware issue is inadequate. Now that I am out of warrentee, gm has not resolved the issue and now I am having shifting problems.

NHTSA ID

11661620

Incident

May 12, 2025

Cracks in the rear sliding window plastic upper rail glass guide causing Rear window leaking water and causing mold from water leaking. GMC has a service bulletin number 18-NA-383 knowing of this issue and not telling customers purchasing the GMC vehicle. The service bulletin was released in 2019 before purchasing the truck and they still didn't inform the customers. My child rides in the back in a car seat and now has been breathing in this mold and mildew for how long. I have had my vehicle in with Titus will Gmc in olympia multiple times for service and inspection of various recalls and still didn't inform me of this issue.

NHTSA ID

11660995

Incident

Apr 20, 2025

Tailgate unlatches unexpectedly. Has happened while parked and while driving. Almost caused accident to others.

NHTSA ID

11660582

Incident

May 9, 2025

The contact owns a 2020 GMC Sierra 2500. The contact received notification of NHTSA Campaign Number: 24V797000 (Power Train); however, the part to do the recall repair was not yet available. The local dealer was contacted. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The manufacturer was not made aware of the issue. The contact had not experienced a failure. Parts distribution disconnect.

NHTSA ID

11658105

Incident

May 1, 2025

The contact owns a 2020 GMC Sierra 2500. The contact stated that the vehicle was under NHTSA Campaign Number: 24V797000 (Power Train) and the vehicle was repaired. The contact stated that after the recall repair, the transmission started shifting hard. The vehicle was taken to the dealer, and the contact was informed that the transmission module would reprogram and adjust independently. The contact stated that a week later, while driving approximately 45 MPH, the vehicle started to run rough, and the message engine power reduced was displayed. The transmission fault, parking brake system alert, service parking brake, and the check engine warning light illuminated. The vehicle was towed to the dealer, who diagnosed the vehicle and determined that the fuel injector was open, causing high resistance in the connector for cylinder #4. The transmission could not be diagnosed until the injector was repaired. The manufacturer was informed of the failure and opened a case. The failure mileage was 125,000.

NHTSA ID

11655399

Incident

Apr 7, 2025

Mileage

125,000 mi

I have a notice of a recall for the transmission control module and I took it to a GMC dealership and they are refusing to fix it. The transmission will not shift so I am unable to drive it

NHTSA ID

11651369

Incident

Mar 28, 2025

The contact owns a 2020 GMC Sierra 2500. The contact stated that while driving at various speeds, the steering wheel was pulling to the left unintentionally. Additionally, the contact stated that there was significant play in the steering wheel. The contact stated that while driving 35-40 MPH and driving through a puddle of water, the vehicle veered violently at a 60-degree angle into the left lane while the contact was firmly grabbing the steering wheel, nearly causing a crash. The vehicle was taken to the dealer and was diagnosed with upper steering shaft failure. The contact was informed that the upper steering shaft needed to be replaced. The part was replaced. Additionally, the vehicle was taken to a Tire Shop, where the tires were replaced and alignment was performed. The vehicle was repaired. The manufacturer was not notified of the failure. The failure mileage was approximately 31,800.

NHTSA ID

11649531

Incident

Feb 13, 2025

Mileage

31,800 mi

ODI # 11646185 My truck on [XXX] leaked transmission coolant from the jumper line leak( which this part is recalled but not for my VIN #) $400.61 dollars and left me stranded in the middle of the highway and had to be towed. After the repair and checking the transmission was discovered it was ruined because of the leak. So now I have to have a new transmission installed at Jennings in Beardstown IL to the cost of $7363.39. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11648985

Incident

Mar 2, 2025

Transmission not shifting correctly. Have had the recall software update. Two new valve bodies and still not shifting correctly. Transmission is known to lock up.

NHTSA ID

11648752

Incident

Feb 3, 2025

My truck had been sitting idling for about 20 minutes on a job site on flat level ground. I turn around for whatever reason and my truck is driving forward with on one in it but my dog. The truck ran into an out rigger on my crane. I had 3 of my employees there that witnessed this happen. I got into my truck and the shifter was in drive. Somehow my dog was able to shift my truck into drive from park while it was sitting idle. I have 3 eye witnesses as well as pictures of the incident. I have pictures but was no able to upload them to they portal.

NHTSA ID

11646739

Incident

Jan 10, 2025

The contact owns a 2020 GMC Sierra 2500. The contact stated while driving 30 MPH, the engine revved while the vehicle lost motive power in the middle of the road. The contact was unable to pull over to the side of the road. The vehicle was restarted but was undrivable. An unknown warning light was illuminated. The contact stated that while the vehicle was being towed, there was a significant amount of fluid leaking onto the ground. The vehicle was towed to Ryan's Repair, where it was diagnosed with a fractured transmission cooler line. The vehicle was not repaired. The mechanic related the failure to an unknown recall. The dealer was not notified of the failure. The manufacturer was notified of the failure, but no assistance was provided because the VIN was not included in the TSB. The failure mileage was approximately 112,000.

NHTSA ID

11646185

Incident

Mar 2, 2025

Mileage

112,000 mi

Vehicle was parked in a school parking lot. Rear Trailer Harness and modules in back short circuited causing an electrical fire that expanded to the driver’s taillight rear bumper, and bed of truck.

NHTSA ID

11645862

Incident

Mar 1, 2025