2018 Toyota Sienna power train problems
18 owner complaints filed with NHTSA name the power train on the 2018 Toyota Sienna — 26% of all complaints for this model year.
What owners report
“Vehicle: 2018 Toyota Sienna XLE AWD, VIN [XXX], approximately 112,000 miles. Component: Power Train / Automatic Transmission (UA80F 8-speed). The vehicle has developed a pronounced whining noise from the transmission that rises with road speed, accompanied by harsh/rough shifting. A Toyota dealer…”
filed Jul 14, 2026
“Since owning my 2018 Toyota Sienna, I have experienced hesitation and erratic shifting with my transmission. I have the UA80E transmission which upon research others are experiencing issues with as well. It appears Toyota is not fully acknowledging the problem. The problem is a safety issue as…”
filed Jun 21, 2026
“My 2018 Sienna had developed a whining noise when accelerating. After taking it in to the mechanic, they advised the transmission was failing. Estimated price tag of $6500-7000 to repair. The vehicle has less than 140K miles. Looking at different issues with this make/model and year, it seems like its rather common. I…”
filed Feb 23, 2026
Verbatim excerpts from complaints filed with NHTSA. Reports are not independently verified.
Power Train problems in other Sienna years
| Year | Reports | Share |
|---|---|---|
| 2022 Sienna | 2 | 2% |
| 2021 Sienna | 8 | 5% |
| 2020 Sienna | 8 | 22% |
| 2019 Sienna | 7 | 16% |
| 2017 Sienna | 36 | 24% |
| 2016 Sienna | 3 | 4% |
| 2015 Sienna | 12 | 5% |
| 2014 Sienna | 7 | 4% |
| 2013 Sienna | 14 | 8% |
| 2012 Sienna | 17 | 7% |
| 2011 Sienna | 30 | 5% |
| 2010 Sienna | 17 | 10% |
Other reported problem areas on the 2018 Toyota Sienna
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.