2018 GMC Sierra Denali Transmission and drivetrain Problems
- Complaints
- 2about this part
- Share
- 12%of 17 total for the year
- Median mileage
- 87,000miles
- Trend
- Not enough dataFewer than 15 complaints, too few for a reliable trend.
NHTSA recorded 2 complaints about the transmission and drivetrain of the 2018 GMC Sierra Denali, 12% of the 17 complaints for this model year. Where a mileage was given, the median is 87,000 miles.
Fewer than 15 complaints name this part, so treat the figures as a rough indication only.
Example complaints
Selected from NHTSA records; personal details are removed. They are consumer reports, not findings.
“Driving down the highway about 65mph it made a loud clunk and I took it in to service department and they told me I would have to pay about $400.00 to drain the transmission fluid and replace it. I told them m pick up only has less than 15,000 miles on it I don't think this is fair, the service gu said the don't pay for it and other Gmc denali customers had theirs done and problem was solved and I wasn't the only customer that had the issue and cory from alaska auto body said it was safe to drive”
NHTSA complaint #11385369, filed 2020-12“The contact owns a 2018 GMC Sierra Denali 1500. The contact stated that on several occasions while driving at speeds over 30 MPH, the vehicle started shaking abnormally. The contact stated that the vehicle stalled while driving on three separate occasions and stalled twice while slowing down. There was no warning light illuminated. The vehicle was able to restart each time, but on one occasion, several attempts were needed to restart the vehicle. …”
NHTSA complaint #11728807, filed 2026-04, 87,000 milesRelated service bulletins
- 11019516Apr 17, 2025This preliminary informational (PI) bulletin provides information to dealership personnel that may be helpful when addressing underbody component corrosion with customers.
- 11013069Jan 9, 2025This bulletin provides information on identifying Non-GM Engine Calibrations for Gasoline Engines using the Tech 2 or GDS 2.
- 11011989Nov 27, 2024This service bulletin provides information on the harmful effects of ethylene glycol in transmission fluid.
- 11011205Oct 28, 2024This informational bulletin explains Unscheduled Supplemental Services and the importance of GM Simplified Maintenance Schedules.
- 11009756Sep 17, 2024This bulletin provides information on Policies Applicable to All U.S. Dealers for Engine and Transmission Assembly Replacement Under Warranty, Policy or Customer Enthusiasm and…
- 11009088Sep 16, 2024This service bulletin provides information on some vehicles that may rock or move slightly forward or rearward while in Park at start up after cold soak. This condition may be…
- 11006421Jul 24, 2024GM is receiving damaged (cracked or broken) transmission cores returned to the reman facilities. The damage is being caused either in the removal process by the technician, or…
- 11005311Jul 9, 2024This service bulletin provides information on Driveline Clunk Noise and what is acceptable and what is considered normal operation.
- 11001321May 16, 2024This bulletin provides information on the harmful effects of water or ethylene glycol in transmission fluid.
- 11000119Apr 26, 2024This service bulletin provides technicians with information to help identify the differences between what is considered a fluid leak, and what is considered fluid seepage.
Transmission and drivetrain: other model years
Other parts of the 2018 GMC Sierra Denali
5 complaintsBrakes
4 complaintsBody and structure
4 complaintsExterior lighting
3 complaintsSteering
3 complaintsElectronic stability control
2 complaintsOther or unknown
1 complaintsSuspension
1 complaintsWheels
1 complaints
← All problems reported for the 2018 GMC Sierra Denali
About this data. Data from NHTSA (ODI) complaints, recalls, TSBs and investigations, updated Oct 31, 2026. Complaints are unverified consumer reports and may be duplicated or inaccurate.
To check a specific vehicle for open recalls, use its VIN at nhtsa.gov/recalls. Methodology