2023 GMC Sierra 2500HD: Power Train complaints
Owner-reported issue (NHTSA complaints, not a recall)
Symptoms
NHTSA has 20 owner complaints for the 2023 GMC Sierra 2500HD that list the power train component. Complaints are individual owner reports, not verified defects.
Examples:
- NHTSA complaint ODI #11748895 (filed 07/07/2026): “On xxx, i was towing my camper to copper center, alaska from palmer, alaska when my truck experienced a full transmission shut down which put the truck into "reduced power mode". we descending down the road right next to victory bible camp (64741 victory rd, sutton-alpine, ak 99674) when the exhaust…”
- NHTSA complaint ODI #11713060 (filed 01/24/2026): “Driving at approximately 30-35mph merging in traffic, the transmission shuttered and went into reduced power mode. ecm reported a 747 code and valve body failure.…”
- NHTSA complaint ODI #11710403 (filed 01/12/2026): “Summary of issue on [xxx], my family and i departed kansas city, missouri, for a camping trip to great smoky mountains national park (cades cove), tennessee, approximately 800 miles away. we were towing a 2020 forest river salem fsx/rtx travel trailer, estimated at approximately 6,000 pounds loaded,…”
Likely causes
These complaints do not establish a single root cause; read the examples above and get a diagnosis.
Fix, in plain English
No single fix is established by these reports. Check your VIN for open recalls at nhtsa.gov/recalls, ask a dealer about technical service bulletins (TSBs) or extended warranty coverage, then have the system diagnosed.
DIY difficulty: Pro
Diagnosis needs a scan tool; repair or replacement needs a lift, transmission jack and the manufacturer's fluid fill/relearn procedure. (Our assessment.)
Cost
No sourced cost range for this issue. Get a written quote after diagnosis.
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