2018 Toyota Sienna Power Train

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.

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.

My husband and I bought this van brand new 6 years ago. We have taken very good care of it and have had it serviced only at the dealership. We haven’t had any problem with the van outside of regular maintenance. On 10/29/25, I had a van full of children when I felt a slip in my acceleration and a warning light came on that read, “ A malfunction in the electronic control of the engine, throttle, or automatic transmission has been detected. Contact your dealer in order to have your vehicle inspected immediately.” Thankfully, I was able to get it to the parking lot. The van didn’t leave that parking lot until the next morning when we took it directly to the dealership. That is when we were told the solenoid and the transmission had gone out. We had to have the whole thing replaced. The van only had 89,388 miles on it.

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.

Whining sound coming from vehicle while in drive and accelerator is depressed. Confirmed by dealership that the transmission is failing and needs replacement.

Transmission Whine and Hesitation. Low gear it will hesitate from stop. Know issue with this transmission. There should be a recall on all ua80 transmissions.

This is a reoccurring issue on numerous occasions but the transmission programming is a danger to drivers when it is in economy mode (the default setting when car starts up). The transmission constantly starts at a higher gear (3rd or 4th) and reduces throttle input from a stop. It makes for a slower takeoff when making a right turn on the stop sign because the engine would be lugging. Similarly when trying to overtake or merge lanes and you try to speed up the vehicle, the car does not want to downshift. The above mentioned problems are not there when eco-mode is disabled or the car is put into sport mode.

There has been a "whining" noise or "hum" upon acceleration noticed for several months to a year, could be longer, but getting worse over time. There is also a delay when pressing on gas for the vehicle to actually accelerate. I have had many instances where I am almost hit from behind because of this delay. Obviously the person's behind me have been following me entirely too closely, but nonetheless, scary. This is our primary vehicle for our family, which carries 4 precious boys. I am aware of the CSP already in place for this issue but have been told that my specific vehicle does not qualify for the customer protection program. That seems very odd given the amount of vehicle's listed as "affected"(83,700) sienna's and 66,500 highlanders. You cannot tell me that there are not more out there like mine that are having the SAME problems but being told "not covered". I do not think anyone should have to drive a vehicle with children in it that you are unsure when your transmission is just going to go out or fear getting hit from behind because of the delay in acceleration. Please please do something about this in order to hold toyota accountable!

The contact owns a 2018 Toyota Sienna. The contact stated while driving at an undisclosed speed, the vehicle hesitated while accelerating. Several unknown warning lights were illuminated. Additionally, the "Pull Over - Take to Dealer" message was displayed. The vehicle was taken to the dealer, where it was determined that the transmission needed to be replaced. The vehicle was not repaired. The manufacturer was made aware of the failure and confirmed that the VIN was not included in Customer Support Program: ZJC (Coverage for UA80 Transmission). The failure mileage was approximately 132,000.

DELAY IN DOWNSHIFTING WHEN THROTTLE IS PRESSED. A DELAY OF 1 TO 2 SECONDS OCCURS THEN ABRUPTLY DOWNSHIFTS AND THE ENGINES REVS LOUDLY.

2018 TOYOTA SIENNA LE. CONSUMER WRITES IN REGARD TO DELAYED ACCELERATION WHICH IS CAUSING TRANSMISSION DAMAGE. *AS *TR