2021 GMC Sierra 1500 Owner Complaints

Excessive oil consumption. I am fearful that my vehicle engine will lock up.

NHTSA ID

11767091

Incident

Sep 26, 2026

I own a 2021 GMC Sierra 1500 AT4 with the 3.0L Duramax diesel. The vehicle developed severe transmission problems, including harsh/jerky shifting and a hard clunk when shifting into reverse. The vehicle was subsequently diagnosed with an internal transmission failure. The repair facility informed me that the transmission gears had failed and caused damage to the transmission and stated that the failure appeared to be related to a manufacturing issue. The repair facility also advised me to watch for a future recall because they believed this could be a widespread issue occurring in other vehicles. I am submitting this complaint so the failure can be documented and considered along with other reports of transmission failures involving this vehicle.NOTE FROM AUTOSHOP:TRANSMISSION FAILURE WAS DUE TO A MANUFACTURE DESIGN FLAW, NOT DUE TO THE CUSTOMER'S DRIVING HABITS. THE PUMP ORIGINAL DESIGN IS WITH SLANTED GEARS AND THE GEARS ARE FORCED AWAY FROM EACH OTHER AND PLACING TOO MUCH STRAIN THE BEARINGS ANI THE BEARING FAIL. AN UPDATE PERFORMED TO HAVE STRAIGHT CUT PUMP GEARS TO AVOID BEARING DAMAGE. CDF DRUM AND CENTER SUPPORT CHANGED TO UPDATED PARTS THAT ARE HEATED TREATED TO AVOID DAMAGE

NHTSA ID

11766718

Incident

Aug 18, 2026

Purchased a used 2021GMC SIERRA in Mar. 2025 from W&K GMC Sedalia Mo. Two mths ago ([XXX]) noticed an occasional slipping in transmission, wheels lock up. The truck would slip, lock for 1-4 seconds and then return back to normal driving. Has done this while accelorating and while driving down the highway. I took truck to my local repair garage who indicated it was most likely the torque converter and it would need to be taken to the dealership for repair. After mechanic commenting that he had seen several GMCs with the same problem, I looked up GMC recall and found that this issue did have a recall on 2020 - 2022 GMC SIERRA TRUCKS ( ours is a 2021)! When my VIN did NOT show any recalls, I called W& K GMC in Sedalia on 9-23-26 and spoke with the shop who told me MY truck did not have the recall notice and it would cost me $160 out of pocket for a diagnostics and $600 -$800 for a converter to even be flushed to see if problem resolved PRIOR to any part replacement. They would have to charge me full price for this repair since MY VIN DID NOT HAVE A RECALL, BUT THE SAME TRUCK MODEL, YEAR, AND ENGINE HAS OTHER RECALLS? I called GMC customer service line on 9-23-26, spoke with customer service agent Tanika, she documented the same info. and could not explain why a 2021 Sierra with the same problem as a 2020-2022 Sierra was not included in this recall that it must have been manufactured in a different facility? The fact that my local garage mechanic in a very small town, has already seen SEVERAL GMC trucks with the SAME PROBLEM, leads me to believe this is a WIDE SPREAD PROBLEM, that GMC is choosing to ignore due to the cost of repairs involved. I am requesting an investigation into HOW MANY RECALLS HAS GMC SENT OUT AND REPAIRED? AND SPECIFICALLY WHY AFTER 3 YRS OF PRODUCTION BY GMC DO THEY BELIEVE A TRANSMISSION PROBLEM WAS ONLY CERTAIN VEHICLES AND NOT ALL THE VEHICLES? This is a huge safety concern if wheels lock up on hwy at 70mph due to malfunctioning TC INFORMATION REDACTED PURSUANT TO THE FREEDOM OF I

NHTSA ID

11766353

Incident

Aug 10, 2026

On [XXX], my vehicle suffered a complete loss of propulsion on the highway, displaying fault codes P0324 and P0016. The vehicle was taken to Boyd's Tar Heel Chevrolet in Roxboro, NC, where the engine block was replaced under the official GM 6.2L engine safety recall.The truck was delivered back to me, and on the very first day I drove it—only 28 miles from my house—it suffered a secondary catastrophic loss of propulsion on the highway on [XXX]. The check engine light began flashing violently, indicating an immediate catalyst-damaging safety hazard, and the vehicle displayed fault code P0307 (Cylinder 7 Misfire).The dealership explicitly instructed me to stop driving the vehicle immediately, authorized the recovery, and told me to bill the tow directly to them. After towing the vehicle back to their facility, Boyd's Tar Heel Chevrolet reversed their position. They are now attempting to hold me financially responsible for the towing fees, along with spark plugs, wiring, and fuel injector services, claiming the failure is due to routine maintenance.This represents a severe highway safety hazard, a direct failure of the manufacturer's official recall remedy, and potential dealer misconduct to avoid liability under the active NHTSA Engineering Analysis EA26005 for post-recall 6.2L engine failures. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11766062

Incident

Sep 21, 2026

While driving 40 MPH my entire dash lite up with every known light and the vehicle lost all power. The dealer stated I need an entire engine replacement, as with Many 6.2. My vehicle is 1 months out side of the recall, it has the exact symptoms and the exact damage as the recall.

NHTSA ID

11765344

Incident

Sep 15, 2026

Both of my upper ball joints wore out and one broke as I was driving down the road at 65 miles an hour pulling me into the on coming lane of traffic, there was no warning of this. I had both upper and lower ball joint replace. If there had been another vehicle coming in the on coming lane we would have had a head on collision. At an earlier date the motor in this same truck had a fallen lifter which cause my motor to loss power, I was able to take it to the local GM dealer and they fixed it, there was no warning this was happening either. I am worried I will have a catastrophic engine failure and GM will not cover this. I have looked up my

NHTSA ID

11765281

Incident

Jul 20, 2026

NUMERO DE VIN FALTANTE

NHTSA ID

11764993

Incident

Jul 22, 2026

The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving at various speeds, the tailgate opened independently. The failure occurred several times and became more persistent recently. The contact stated that while the vehicle was parked in the driveway, the side marker lights started flashing, and the tailgate opened. Additionally, upon exiting a store, the contact discovered that the tailgate had opened while the vehicle was parked. The dealer and the manufacturer were notified of the failure and confirmed that the VIN was not included in a recall. The failure mileage was approximately 66,000.

NHTSA ID

11764674

Incident

Sep 9, 2026

Mileage

66,000 mi

Dashboard keeps returning to aljarir type writing. We bought it with American English but won't stay in English. Monday will be 30 day and I believe the dealer is ghosting me. Y'all have any ideas how to reset the dashboard without replacing the radio??? Closest answer I was given.

NHTSA ID

11764558

Incident

Aug 20, 2026

The contact owns at 2021 GMC Sierra 1500. The contact stated that while driving 60 MPH, the engine was overheating. The message "Reduce Engine Power" was displayed. The contact shifted to neutral to reach the dealer. The contact associated the failure with Special Coverage: N252508341; however, the VIN was not included. The dealer diagnosed the vehicle with coolant control valve failure, and the vehicle was repaired. The manufacturer was made aware of the failure and stated that the cost of the repair was not covered under the special coverage program. The failure mileage was approximately 94,328.

NHTSA ID

11764209

Incident

Sep 12, 2026

Mileage

94,328 mi

Check engine light came on my vehicle (104,000/mi) and fans came on while truck was off. Took to dealership and techs diagnosed vehicle as having bad "coolant flow control valve". Dealership ran VIN check as there is a GM "extended special coverage program" N252508341 for the LM2 motor, which my vehicle has. However, N252508341 only applies to vehicles in CA. The dealership did not cover my repair. I filed a complaint with GM who denied it due to the program being only applicable to CA trucks. I was advised to file a complaint with NHTSA as the only avenue with recourse. I would like if NHTSA intervened and made GM honor the program in all 50 states and I be offered a refund for the $2500.00 repair I had to pay for. Thank you.

NHTSA ID

11763611

Incident

Aug 24, 2026

The engine coolant control valve on my 2021 GMC Sierra 3.0L Duramax diesel failed. This specific component failure triggers an active vehicle 'No-Restart' safety event during automatic engine stop/start operations (per GM Service Bulletin #24-NA-070). This condition can suddenly prevent the vehicle from restarting when stopped at intersections or in active traffic, creating an immediate highway safety hazard and leaving the vehicle stranded. Additionally, the vehicle's radiator cooling fans run continuously at 100% maximum capacity as a system fail-safe, creating severe electrical drain. General Motors has issued a Special Coverage Adjustment (#N252508341) acknowledging the high failure rate of this part, but it is capped at 150,000 miles. Because this defect causes unexpected stalling/no-start safety risks in live traffic past this arbitrary mileage limit, a formal safety recall is required.

NHTSA ID

11763419

Incident

Sep 10, 2026

Engine stop working, lots of black smokes through the exhausts and vibrating weird. Lifters failed amoung other parts and they deemed the engine bad so they replaced it with a new one. The new engine started to make the same weird noises.

NHTSA ID

11763347

Incident

Jun 14, 2026

Catastrophic engine failure at 77357 miles. I went to the local GM dealer and my VIN is not in the L87 engine recall. Not sure how to repair my truck , but feel like the engine should not have locked up with such low miles, and I done constant engine maintenance , meaning oil changes every 5K miles.

NHTSA ID

11763146

Incident

Sep 8, 2026

Catastrophic Engine Failure due to Lifter Failure at approximately 51,000 miles driven. This has been confirmed by the dealership and reported/escalated to General Motors. The truck is at the dealership for repairs. General Motors offered to cover 65% of the repair as a Goodwill sign. As the 60K powertrain warranty had expired. This truck has the same components that are covered under the recall for the same model year. However the recall only extends to March 1, 2021 Manufacture date. My truck was manufactured a few weeks prior to that so it was not included. GM refused even discuss this could be potentially due to a recalled issue. Multiple warning lights and error messaged were present on the dash indicating issues when it failed. Additionally, a loud metallic knocking noise was present at speed and idle. Power was significantly reduced and the engine was running very rough.

NHTSA ID

11763103

Incident

Sep 1, 2026

Engine I believe The truck died while I was doing 78 MPH on the highway Dashboard stated “shift into neutral and press start” I pulled to the side of the road and did what it stated and it would not crank over. I also put it in park turned the vehicle off and back on to try to start it. The lights on the dashboard, all gauges, the AC, and everything works the truck just will not crank over. Check engine light came on but is not throwing any codes

NHTSA ID

11763073

Incident

Sep 8, 2026

XXX 2021 GMC Seria 108,339 miles driving home from [XXX] in town and out of nowhere the lights on the dash light up I saw it say adaptive steering and something breaking. There was a lot going on as the steering was rapidly shaking limited breaking while trying to avoid a collision. The engine started a loud knocking sound and sudden smoking out tail pipes. I was able to get the truck stopped turned it off and sat there for a while trying to collect myself. Restarted the truck and slowly drove it to my home 2 miles away. It was flatbed to local GM dealer that quickly diagnosed it saying heavy smoke knocking needs New Engine! They won't confirm exactly what the internal engine failure is. Other than its Failed. The engine build date is 2020 day 350 My VIN is not currently in the current GM engine recall However it's certain this failure is totally related to GM's engineering design and Manufacturing issues. Look deeper into the recall date ranges this failure is clearly a victim. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11762994

Incident

Aug 31, 2026

Coolant Control Valve failure. This vehicle year is included in a GM bulletin that extends the Coolant Control Valve replacement coverage to 150K miles due to a faulty design. My is valve failing exactly as described in the bulletin and GM will not cover the replacement due to my vin number. The vehicle randomly goes into reduced power whereby it is prohibited from safely keeping up with traffic. Research shows that there are a significant number of owners in my same situation where GM is denying repair and replacement coverage.

NHTSA ID

11762983

Incident

Sep 1, 2026

Transmission failed, Value Body is listed by dealer as the cause. GMC is saying that my vehicle is not part of the recall, even though it is part of the same model, same years as well as the same problem, the value body on the transmission. See estimate from dealership Tucks GMC Hudson, MA TRANSMISSION REPLACEMENT WITH BYPASS VALVE $6800.00 RADIATOR REPLACEMENT LEAKING $1980.00 ABS TRACTION LIGHT WHEEL SPEED SENSOR $395.00 CHECK ENGINE LIGHT IS ON NEEDS PCV VALVE HOSE AND SOLENOID $430.00 OIL LEAK BETWEEN ENGINE AND TRANSMISSION ?

NHTSA ID

11762717

Incident

Jun 12, 2026

I was notified my lifters in my 6.2 L V8 would need to be inspected for any defects. When I purchased my vehicle from Car Max here in Jackson, MS, I received a notification from the dashboard that the engine oil was low and to add oil. I turned around and took it back to the dealership as soon as possible. This happened on the first day of owner ship with in 5 minutes of driving off from the lot. I Car Max told me to just add oil and bring them the receipt and they would reimburse me. I chose not to and asked them to service the vehicle to avoid any issues with my warranty or my Car Max Shield Warranty. 2,000 miles later the same notification came across the dashboard again. I took it back to Car Max immediately and they ended up sending it off to my local GM dealership for service. They topped it off with oil after inspecting it for any leaks in the engine. None were discovered. After the 3rd notification about the engine oil level being low after close to 3,000 miles, they serviced the vehicle and put the vehicle under the Oil Consumption Watch. This took place from October 2025 through September 2026. After multiple visits, they informed me they would need to perform further test to see if the lifters were failing and that I would be responsible for the labor fees estimated at around $632.82. I informed them I have Car Max’s 150,000 mile warranty. Fidelity Insurance company informed me they would need to send an inspector out to the GM dealership. Before this takes place, they would need the vehicle to undergo various tests and I would be responsible for the labor fees. Should the engine components be found worn down. Fidelity would not cover the repairs. Should the engine components be found defective, they would cover the replacement part but not the label. Labor costs would estimate around $2,978.95. I asked the GM dealership to share this information with me in writing for documentation purposes. I asked for my vehicle to be parked until further notice.

NHTSA ID

11762400

Incident

Sep 3, 2026

Lifter locked up causing bent push rod. This situation caused truck to strand the driver without warning. Truck needed to be towed. This repair was performed by the dealership and is a known issue with 6.2 L engine.

NHTSA ID

11761850

Incident

Apr 29, 2026

Loss of power, had engine repaired, replaced passenger side head and cylinder. Now drivers side is having the same issue.

NHTSA ID

11761457

Incident

Mar 2, 2026

Transmission stopped at 29,000 miles, engine died and was replaced at 32,000 miles

NHTSA ID

11761314

Incident

May 15, 2024

Cam Shaft and Lifter failure. Lifters were replaced 3 times

NHTSA ID

11761107

Incident

Aug 1, 2026

Driving on the highway lost proportion/acceleration, loud knocking coming from the engine

NHTSA ID

11760509

Incident

Aug 28, 2026