2017 Toyota Sienna power train problems

“I own a 2017 Toyota Sienna XLE Premium, FWD, 8-passenger,equipped with the UA80E automatic transmission. At approximately 150,000 miles, the transmission began making a whine in 3rd gear and higher, most noticeable under steady throttle and worse after the vehicle warms up. The sound appears to come from the transmission, but the exact failed component has not been confirmed. A drain and refill with Toyota ATF WS reduced the noise temporarily, but it returned after about 1,000 . The vehicle had approximately 156,000 miles when I last tracked the issue. I am concerned this may be an internal transmission bearing or other component failure. A transmission replacement or rebuild could cost thousands of dollars and Toyota has a ZJC but I’m told my vehicle isn’t covered although it fits the dates and requirements. I am reporting this issue to document the failure and ask NHTSA to investigate whether other 2017 Sienna vehicles equipped with the UA80E transmission experience similar whining or premature internal wear.”

“The contact owns a 2017 Toyota Sienna. The contact stated that while driving at various speeds, a whining noise was coming from the transmission. The vehicle was taken to the local dealer, who diagnosed that the transmission was faulty and needed to be replaced. The vehicle was not yet repaired. The manufacturer was notified of the failure. The contact was informed of the extended coverage related to the failure. The failure mileage was 95,000.”

“Transmission has high pitch wine that is consistent and rises with speed... Toyota expains I have 500 to 5000 miles before carrier bearing completely fails... Toyota has an extended warranty for Sienna UA80e transmission in 2017/2018... The issue is exactly as they explain in their warranty extension for 10yrs, unlimited miles... My vin number did fall on their list... BUT it is the exact issue... It should be covered, especially since they know !!”

“I, as well as other owners of 2017–2018 Toyota Highlanders and 2017–2018 Siennas are experiencing serious transmission issues—including high-pitched whining, erratic shifting, clunks, hesitation, and premature failure. My 2017 Toyota Sienna has the UA80 8-speed automatic transmission at issue and started whining upon acceleration in March/April 2026 timeframe. It has always had the clunking and hesitation problem. According to Gears Magazine, the issue stems from a flawed assembly process involving the counter drive gear support. A locking tab meant to secure a vital retaining nut was not bent properly during factory assembly. This leads to gear movement, internal wear, whining, and eventually failure. Unknown to me, in 2019, Toyota had acknowledged the problem in Technical Service Bulletins T-SB-0160-18, T-SB-0008-21, which only go to dealers, and implemented a limited Customer Support Program (CSP ZJC)—but only offered coverage to a narrow group of VINs, not to all VINs for model years that have these transmissions. My car is experiencing these same symptoms. My Toyota Dealer confirmed this problem and recommended a transmission replacement for $11,000…”

“I have a 2017 Toyota Sienna XLE with about 120k miles on it. Out of nowhere the transmission was gear hunting and surging. It eventually became impossible to get it above 30 mph. It seemed like the transmission just went haywire. No lights on the dash let me know anything was wrong. Thankfully I had just pulled off the highway. Otherwise it could've been bad. I couldn't drive it safely so I had it towed to the nearest Toyota dealership. They said that the transmission needed to be replaced. $9k....”

“We experienced a high whine for a couple of months. No codes were being read by any mechanics. Then the transmission started slipping between 2nd and 3rd gears, and then we couldn’t reverse. Now it’s not switching gears at all. There is a recall for our year and type of transmission, for this issue, but our vin number is not included in that recall.”