2015 GMC Sierra 1500 power train problems
97 owner complaints filed with NHTSA name the power train on the 2015 GMC Sierra 1500 — 14% of all complaints for this model year.
What owners report
“My 2015 GMC Sierra 1500 SLE has the 6L80 transmission. While traveling on the interstate with my fiancé, the transmission failed. It was towed to a garage and they informed me that it needed to be replaced.”
filed Aug 6, 2026
“For no apparent reason the truck goes into “low power mode” and gives off code p2138 often happens around 30-35 mph. Have had it happen to me also around 45 mph also. I have replaced sensors and parts to which a month or so goes by and it happens again.”
filed May 26, 2026
“Power steering seems to be lost for a second or two at low speeds turning. Happens multiple times a day.”
filed Sep 10, 2026
Verbatim excerpts from complaints filed with NHTSA. Reports are not independently verified.
Power Train problems in other Sierra 1500 years
| Year | Reports | Share |
|---|---|---|
| 2026 Sierra 1500 | 25 | 23% |
| 2025 Sierra 1500 | 24 | 21% |
| 2024 Sierra 1500 | 68 | 19% |
| 2023 Sierra 1500 | 91 | 19% |
| 2022 Sierra 1500 | 108 | 19% |
| 2021 Sierra 1500 | 134 | 24% |
| 2020 Sierra 1500 | 96 | 21% |
| 2019 Sierra 1500 | 136 | 21% |
| 2018 Sierra 1500 | 128 | 43% |
| 2017 Sierra 1500 | 117 | 33% |
| 2016 Sierra 1500 | 83 | 24% |
| 2014 Sierra 1500 | 69 | 9% |
Other reported problem areas on the 2015 GMC Sierra 1500
Counts are unique NHTSA complaints naming this component group. Complaints are unverified owner reports; mileage is computed only from complaints that included a usable odometer reading.