GMC Sierra Complaints (2026)

171 consumer complaints on file.

#11710215January 11, 2026
ELECTRICAL SYSTEM, ENGINE, FUEL/PROPULSION SYSTEM
2026 Sierra 1500 AT4 with 3.0L Duramax Diesel. Three major issues. 1. 2960 miles, thrust bearing failure caused low oil pressure and internal damage. Vehicle needs complete engine replacement. The truck is still at the dealer with no ETA on engine arrival and replacement. 2. Vehicle has severe electrical issues. battery replaced on second day of ownership due to over charge and smoking. The truck would randomly lose the ability to produce sound through infotainment system on start. This includes warning sounds and audible turn signal sound. Dealer said it’s caused by faulty Amp which was replaced. 3. The truck shut off (full system shutdown) and the transmission failed over to neutral while driving on the highway and failed to restart. Barely restarted on second attempt. Dealer has no idea why it is doing it. However the vehicle was throwing multiple code related to transmission module failure, brake module failure, transmission module failure, etc.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11708994January 5, 2026
ENGINE
3.0 Duramax Engine Failure - 2026 GMC Sierra 1500 Denali Ultimate at just 6,755 miles and only 77 days of ownership. Within the first few thousand miles, the truck intermittently had warnings appear of “reduced acceleration, drive with care”. The truck would limit its ability to maintain speed. When it occurred during highway driving, it was particularly dangerous. The check engine light would also come on. After parking the vehicle for a bit and restarting it, things returned to normal. At the dealership, we reported the issue and leaned the computer reveled a P06DD code which required them to check the crankshaft for excessive play. Our truck was out of specification requiring complete engine replacement at just 6,755 miles. “Service Bulletin 25-NA-307 which states this code may set due to thrust bearing failure. following 25-NA-307 checked crankshaft end play and got a reading of 0.3400 in. the maximum spec is 0.0124 in.“ GM and Laura Buick GMC should not have sold this truck to us without inspecting it for this known issue. This extensive repair required complete removal of the cab from the chassis.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11707315December 28, 2025
POWER TRAIN
My 2026 GMC 1500 is equipped with the 2.7L L3B & 8L90 Transmission. At approximately 1000 miles, I noticed that in 2nd between 2700-3200 RPM, a vibration could be felt throughout the cabin and would occur whether with or without throttle application. I am able to recreate the issue during hard acceleration or placing in manual mode. No matter the Vehicle mode selection (sport, normal, snow, tow/haul, etc.), the issue still persists. I took the vehicle to a local GMC dealer at approximately 6K miles to diagnose. I requested that we test drive another 1500 with the same 2.7L and Transmission. They brought out a 2026 Elevation Quad Cab with the 2.7L; less than 20 miles on the odometer.The same vibration was present in 2nd gear at same RPM band. I requested that the issue be escalated to a local GM rep. for further investigation. However the response from the dealer was inadequate and basically stated that no warranty work would be considered because it seems to be “normal operation”.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11707327December 28, 2025
VEHICLE SPEED CONTROL, FORWARD COLLISION AVOIDANCE: ADAPTIVE CRUISE CONTROL
Component/system malfunctioned: Adaptive Cruise Control integrated with Traffic Sign Recognition/Speed Limit Assist (camera-based speed sign detection and automatic speed adjustment). Vehicle available for inspection upon request. While driving ~35 mph in 35 mph zones with Adaptive Cruise Control engaged, the system repeatedly misread speed signs (or GPS data) as much higher (e.g., 75 mph). The vehicle then automatically accelerated aggressively toward the incorrect higher speed without driver accelerator input. Acceleration is sudden and strong due to electric powertrain torque. This problem can be reproduced in multiple locations in low-speed zones. Safety risk: Vehicle sped up dangerously in restricted areas (residential, traffic, pedestrians), risking loss of control or collision before I could brake or disengage system. No crash/injury occurred, but risk was high. Problem not reproduced/confirmed by dealer or service center. Vehicle/component not inspected by manufacturer, police, insurance, or others. No warning lamps/messages/symptoms before acceleration; dashboard briefly showed incorrect higher limit. First occurrence UNKNOWN, but multiple incidents since ownership. Appears to be defect in software, camera recognition, or integration of Traffic Sign Recognition with Adaptive Cruise Control, causing unintended high-speed acceleration in low-speed areas.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11704497December 11, 2025
ELECTRICAL SYSTEM, SERVICE BRAKES, HYDRAULIC
The contact owns a 2026 GMC Sierra 1500. The contact stated that upon starting the vehicle and shifting into reverse(R), the vehicle failed to move while depressing the accelerator pedal. The contact felt a hesitation while depressing the brake and accelerator pedals, and the contact then attempted to restart the vehicle. The contact restarted the vehicl;e however, while attempting to accelerate, the brakes independently activated. Despite the repeated failure, the contact was able to pull into a gas station to restart the vehicle. The contact stated that after several attempts, the vehicle finally resumed normal operation, and the contact drove the vehicle to the residence. The next day, the contact test drove the vehicle, and the failure reoccurred while the contact was attempting to park the vehicle in a parking spot. The vehicle was taken to a dealer, where a diagnostic test produced 7 fault codes; however, the mechanic was unable to repair the vehicle. The manufacturer was notified of the failure, and the manufacturer stated that there was a communication disconnect between the contact and the dealer. A case was filed with the manufacturer. The vehicle was not repaired. The failure mileage was approximately 300.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11704612December 11, 2025
UNKNOWN OR OTHER
I saw the report regarding models of Chevrolet trucks not receiving owners manuals from factory. I purchased a 2026 GMC AT4 in early October 2025. It didn't come with a manual either. I emailed my sales person at Ewing GMC in Plano, Texas informing him that it was missing the manual and I was told that GM had decided to only include physical manuals with Denali grade trucks. This didn't make any sense whatsoever. I would prefer to have a physical manual available to reference in the event of vehicle issues.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11703773December 8, 2025
SERVICE BRAKES
Car rolls after parking brake is set. This happens on low hill grade and high hill grade parking location.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11701463November 25, 2025
SUSPENSION, ELECTRONIC STABILITY CONTROL (ESC)
The contact owns a 2026 GMC Sierra EV. The contact received notification of NHTSA Campaign Number: 25V594000 (Electronic Stability Control (ESC); however, the part to do the recall repair was unavailable. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The contact stated that while driving over uneven pavement, there was an abnormal bumping sound coming from the front passenger's side suspension. Additionally, the contact stated while driving at various speeds, the contact noticed an abnormal rattling sound coming from nearby the pillars surrounding the infotainment system. There was no warning light illuminated. The dealer was contacted. The vehicle was taken to the dealer, where the contact was informed that the recall repair would take 30 minutes; however, the vehicle had been at the dealer for 15 days, and the recall repair had not yet been performed. The manufacturer was informed of the failure. The failure mileage was approximately 4,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11693972October 16, 2025
ENGINE
I do not have an official communication from the dealer who is servicing my vehicle. However, they have had my vehicle for almost 3 weeks and they tell me that the engine has failed and needs complete replacement. They said the engine lost compression and quit running, it now cranks and does not start. Although the engine has not been disassembled we believe the point fo failure to be in the rotating assembly of the bottom end of the engine.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11689080September 23, 2025
VISIBILITY/WIPER, UNKNOWN OR OTHER
Ac not working properly. Ac blows air to defrost vents foging front windshield and side windows causing bad visibility
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11688564September 20, 2025
SUSPENSION
Rear right clunk in rear suspension. Dealer kept truck for 2 days and can't figure it out. Worried it could be a suspension nut or bolt and could cause a crash.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0

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