2020 GMC Sierra 1500: Power Train complaints
Owner-reported issue (NHTSA complaints, not a recall)
Symptoms
NHTSA has 98 owner complaints for the 2020 GMC Sierra 1500 that list the power train component. Complaints are individual owner reports, not verified defects.
Examples:
- NHTSA complaint ODI #11770894 (filed 10/13/2026): “The contact owns a 2020 gmc sierra 2500. the contact stated that while stopped at a traffic light and making a left turn at approximately 20 mph, the transmission failed. the vehicle was unable to exceed 10 mph. the check engine warning light illuminated, and a dinging sound was heard following the …”
- NHTSA complaint ODI #11767451 (filed 09/28/2026): “The vehicle in questions was purchased with less than 5 miles in year 2020. this vehicle was dropped off at mac haik chevolet madison ms on september 25, 2026. i was advised on september 28, 2026, that the vehicle was test driven with the scan tool connected, graph torque converter slip, found over …”
- NHTSA complaint ODI #11764362 (filed 09/15/2026): “5/5/25 woke up back seat entire truck flooring soaking wet back glass cracked. 4/8/25 transmission went out 117,000 miles 7/3/25 exhaust leak and placed nox 1. 7/8/25 127551 mileage exhaust leak replace gaskets, belt , tensioner, and pulley, 6/8/2025 3 knock sensors replaced and replaced intake mani…”
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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