2026 GMC Sierra 1500 Problems

What owners report

Owners of this model year most often describe sudden engine failures and abrupt shutdowns at low mileage, in many cases requiring engine replacement. A second frequent theme is the transmission slamming into park or neutral, usually during slow turns on an incline, with warnings such as "Service Transmission" and "Shift to Park". A smaller share of complaints describe loss of audio from the infotainment and warning-chime system.

1. 1
   Engine

   Engine failure or seizure at low mileage

   • 62 complaints (42%)
   • median 5,018 mi at 0.8 yrs old (7 state mileage, few)
   • filed 2025–2026

   Owners describe a sudden knock or loud noise from the engine followed by loss of power, reduced-power messages, or a vehicle that will not restart. Several say the dealer diagnosed internal damage, metal in the oil pan, or a spun bearing, and the engine had to be replaced; some owners report waiting weeks or months for a replacement engine. In some complaints the engine was replaced more than once. Mostly reported under about 10,000 miles, often within the first months of ownership, with several cases between a few hundred and a few thousand miles.

   2 related service bulletins

   What to check: Ask for the service history and whether the engine has already been replaced or repaired; a cold start listen for knocking and a check of oil condition and pressure readings are worth doing before purchase.

   2 excerpts from owner complaints in NHTSA records

   “I heard a loud metallic knock that was not consistent with normal engine noise. I noticed the oil pressure was on the lower end of the scale but not abnormal based on how it is displayed. I decided to take the vehicle to the dealer ASAP for an oil change (that was coming due) and discuss with them. I drove roughly 20 miles from start of noise until delivery at the dealer. …”

   NHTSA complaint #11712965, filed 2026-01

   “Catastrophic engine failure. A 2026 GMC Sierra with only 7360 miles had engine failure while driving at 45 miles per hour which resulted in no power from the engine to assist in getting the truck off the road and stopped safely out of the road. In my case, it happened late at night so traffic wasn't an issue. I was just stranded in a dark, rural area late at night. If this happens to someone in traffic, the results may be much different from mine. …”

   NHTSA complaint #11764358, filed 2026-09
2. 2
   Transmission and drivetrain

   Truck shifts into park or neutral on its own

   • 14 complaints (10%)
   • median 2,000 mi at 0.8 yrs old (5 state mileage, few)
   • 1 mention a crash, fire or injury
   • filed 2026

   Complaints describe the truck abruptly shifting into park or neutral and shutting down, often during slow turns into driveways or parking lots on a slight incline, with a grinding or screeching noise and the brakes applying. A "Service Transmission" or "Shift to Park" message usually appears, and the vehicle can often be restarted. Owners report that dealers were sometimes unable to duplicate the problem; in other cases dealers replaced the transmission, a telematics module, or an unstated module. Reported from very low mileage up into the low thousands, typically during low-speed maneuvering on inclines.

   Recall 26V289000 · DO NOT DRIVE2 related service bulletins

   What to check: During a test drive, try a slow turn up a slight incline and a low-speed reverse; ask whether the transmission has been inspected or replaced and whether any related reprogramming was performed.

   2 excerpts from owner complaints in NHTSA records

   “On 10/15/2026 I was making a slow right-hand turn up a slight incline into a parking lot when the vehicle braked very hard and the transmission made a grinding noise. I looked at the dashboard, and it was showing that the truck shifted into park while I was driving. The electronic brake engaged as well. I tried putting the truck back into drive, but it would not go into drive. On the dash there was a Service Transmission warning. The push to start engine button still had the green LED on as if the vehicle was running. …”

   NHTSA complaint #11771425, filed 2026-10

   “While turning right and at a slight incline the truck engine turned off, the transmission made a grinding noise, the truck went into neutral and the dash stayed “Press Start Button”. This is the second time this has happened within 5000 miles of the struck being purchased. Several others have reported the exact same issue on Facebook forums.”

   NHTSA complaint #11766519, filed 2026-09
3. 3
   Engine

   Sudden shutdown with "Transport Mode" or no restart

   • 43 complaints (29%)
   • median 2,950 mi at 0.8 yrs old (8 state mileage, few)
   • filed 2026

   Owners describe the engine cutting out while driving, sometimes with a "Transport Mode On" message, a check engine light, or reduced acceleration, and then failing to restart. Some report the dealer replaced a module or found no cause; others say the vehicle was towed and a case was opened with the manufacturer. Reported at low mileage, often within the first few thousand miles, and sometimes on the highway.

   2 related service bulletins

   What to check: Ask whether any software updates or module replacements were done for stalling or no-start concerns, and confirm the truck restarts reliably from cold and after short trips.

   2 excerpts from owner complaints in NHTSA records

   “Driving on the highway near Rockport, WA, when vehicle suddenly loss propulsion, engine light appeared, and vehicle went into transport mode enabled. Without causing an accident, I was able to pull to the side of the road. Once I put vehicle in park, it shut off and displayed, “Tranport Mode On. Vehicle would not start and was towed home. My son-in-law was able to disable transport mode, but vehicle still will not start. Will notify dealership on Monday.”

   NHTSA complaint #11755699, filed 2026-08

   “Driving on the highway near Rockport, WA, when vehicle suddenly loss propulsion, engine light appeared, and vehicle went into transport mode enabled. Without causing an accident, I was able to pull to the side of the road. Once I put vehicle in park, it shut off and displayed, “Tranport Mode On. Vehicle would not start and was towed home. My son-in-law was able to disable transport mode, but vehicle still will not start. Will notify dealership on Monday.”

   NHTSA complaint #11755698, filed 2026-08
4. 4
   Electrical system

   No audio from stereo or warning chimes

   • 7 complaints (5%)
   • median 3,657 mi at 0.8 yrs old (1 states mileage, few)
   • filed 2026

   Complaints describe intermittent loss of all sound, including radio, turn-signal clicks, incoming calls, and warning chimes, sometimes lasting hours or all day. Owners report dealers reprogrammed the audio control module or reset the radio, and some say a known bulletin was cited but not applied to their vehicle. Reported across a range of mileages, often within the first few thousand miles and on multiple occasions.

   3 related service bulletins

   What to check: Test the radio, chimes, and turn-signal sounds over several starts; ask whether the radio reset or audio module reprogramming has been performed.

   2 excerpts from owner complaints in NHTSA records

   “No sound at different times. No way to reset issue. TSB issued May 14, 2026 for known issue. As of July 6, no estimate on repair. Blinkers make no sounds, Onstar can call but you cannot hear them. In event of accident, no communication.”

   NHTSA complaint #11748779, filed 2026-07

   “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. …”

   NHTSA complaint #11710215, filed 2026-01

Buying note. This is a recent model year with mostly low-mileage complaints, so a careful test drive and a full service history matter more than mileage. Ask specifically about engine replacement history, any transmission diagnostics or repairs, and whether software updates for the audio and stalling concerns have been applied.

Summary written with AI from a sample of 60 NHTSA complaints for this model year (picked at random, with complaints that state a mileage and recent ones taken first), then checked automatically against the source records. Where a problem shows a complaint count, every complaint for this model year was matched with fixed keyword rules (written with AI and tested against the sample), and the mileage, age and repair figures are calculated from those complaints; owners' figures are as stated, not verified. Other counts refer to the sample. The excerpts come from NHTSA's public complaint records and are unverified; capitalisation is normalised, NHTSA staff notes are removed, and shortened text ends with “…”. Something wrong? Request a correction.