-
Power Train
06/01/2026
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 inspected the vehicle and diagnosed a failing transmission requiring replacement. The symptoms and diagnostic trouble codes match those described in Toyota TSB T-SB-0160-18 ("Transaxle Whine Noise, Harsh Shift, MIL ON, or Reduced Power") for the UA80 8-speed transmission. This is the same failure mode Toyota acknowledged in Customer Support Program ZJC, which attributes the defect to a washer/locking tab that was not sufficiently bent during assembly, allowing an internal nut to loosen and causing progressive internal damage. However, this vehicle's transaxle serial number falls outside the range covered by ZJC, so Toyota has not provided coverage despite the identical defect and symptoms....
-
Power Train
06/04/2026
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 sometimes when you go to quickly accelerate (merging, making a turn while starting from a stop, etc) the transmission hesitates and doesn't engage for a few seconds. This is an ongoing problem with the transmission. Toyota really needs to fix these transmissions!
-
Power Train
02/01/2026
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 bought a Toyota for its reputation of getting at least 200K if not more miles. I called both the dealer and Toyota themselves. Both said too bad, so sad - nothing they could do for me.
-
Power Train
11/01/2025
The contact owns a 2018 Toyota Sienna. The contact stated that while driving 30 MPH and ascending a hill, the vehicle started making an abnormal whining sound and hesitated while accelerating. The vehicle was driven to the dealer to be diagnosed. The vehicle was diagnosed with transmission failure. The manufacturer was notified of the failure. The failure mileage was approximately 126,000.
-
Power Train
01/14/2026
Transmission has been whining. A P27137F Code appeared and the vehicle is only in 2WD mode currently. Concerned to drive vehicle due to further damaging transmission or getting stuck while on the road.
