Toyota Sienna harsh shifting problems

Filed Nov 6, 2026 · Transmission · AZ

Since 2018–2019, our 2018 Toyota Sienna has had recurring drivability and suspected transmission problems, including stalling, failure to engage or accelerate when the accelerator is pressed, rough idle, hesitation, and harsh shifting. We reported these concerns to Toyota and filed an the federal safety agency complaint during our first year of ownership. The problems have continued intermittently for years and now include transmission whining, slipping, delayed gear engagement, irregular shifting, and reduced power. Unexpected stalling or failure to accelerate creates a safety risk when entering traffic, crossing intersections, or avoiding hazards. On October 19, 2026, AAA inspected the vehicle following a four-wheel-drive malfunction warning. Its October 20 invoice documents UA80F eight-speed transmission-related fault codes P0740-7E, P2713-7F, and P2756-7F and notes possible sticking valve-body solenoids. Toyota's own Technical Service Bulletin T-SB-0160-18 (issued December 17, 2018; revised May 11, 2021), titled "Transaxle Whine Noise, Harsh Shift, MIL ON, or Reduced Power," applies to certain 2017–2018 Siennas and lists these exact three codes (formatted P07407E, P27137F, P27567F). Toyota's Customer Support Program ZJC, Policy Bulletin POL19-04 (2019), also acknowledges transmission whine, harsh shifting, reduced power, and warning lights in certain UA80-equipped vehicles and describes a possible assembly defect involving a washer tab and loosening internal nut. An authorized Toyota dealer evaluated the vehicle October 24–30, 2026, after receiving AAA's findings but reported it could not reproduce a warning light and that the VIN/transmission serial number were outside program limits. No transmission repair was performed. The vehicle remains unrepaired. Please investigate whether this longstanding safety-related failure affects vehicles beyond Toyota's stated production cutoff.

Filed Jul 14, 2026 · Transmission · FL

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. This represents a safety concern. Based on documented failures of this transmission across the UA80 platform, the condition can progress to loss of power, limp mode, or sudden loss of forward propulsion while driving — including at highway speed and without further warning — creating a risk of a crash or of being stranded in traffic. The vehicle has been maintained through authorized Toyota service. I am requesting that the federal safety agency investigate whether the UA80/UA80F transmission defect warrants a broader safety defect determination and recall, given the volume of similar complaints across affected model years INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Jul 11, 2026 · Transmission · CA

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 including labor. They said my VIN was not included in the Customer Support Program. Driving with a failing transmission is highly dangerous. A bad transmission can cause sudden power loss causing the car to halt to a sudden stop, unintended acceleration, or my car might get stuck in neutral while driving. I could lose control or be unable to get to the shoulder on the highway, cause a rear-end collision, or get stuck in busy traffic. DESIRED OUTCOME REQUEST: My VIN should be covered under the Customer Support Program in the category of cars that are “less than 10 years old regardless of mileage” or a full recall of all VINs of these model years with these transmissions should be executed. Thank you.

Filed May 14, 2026 · Transmission · NC

I am writing to report a safety defect regarding the 8-speed automatic transmission in my 2017 Toyota Sienna. The vehicle exhibits severe hesitation during acceleration, harsh shifting, and a high-pitched whining noise, specifically consistent with the 'whine of death' described in Toyota's Customer Support Program ZJC and related Technical Service Bulletin T-SB-0160-18.Despite these identical symptoms, my vehicle’s VIN is not included in the coverage list. This hesitation during acceleration creates a serious safety issue, as the car fails to accelerate unexpectedly when attempting to merge or cross traffic. My vehicle is equipped with the UA80F/E transmission, which is documented to have a faulty assembly (improperly bent washer tab). I request that the federal safety agency investigate the exclusion of my VIN from this program, as the defect poses a significant risk to passenger safety and the safety of others on the road.

Filed Apr 24, 2026 · NY

[XXX] [XXX] / [XXX] [XXX] 2010 Toyota Sienna Possible Shifter Interlock Failure: On [XXX] my [XXX] child found his way into the driver’s seat of our 2010 Toyota Sienna while the vehicle was parked in the driveway. According to my wife, there were no keys in the vehicle, and the vehicle was in park. In an instant, my wife (who was outside the van) helplessly observed the van begin to roll backward down the driveway and then across the sidewalk (on our side of the street), then across the street, and then across the sidewalk on the other side of the street and into the neighbor’s yard where it finally came to a rest. She said she heard something like grinding gears. I presume my son was trying to put it in park. Thankfully no property damage or personal injuries occurred during the incident. I [XXX] ) was not home when this happened. When I returned home, I inspected the van to see if my son was able activate the emergency shift lock release. I found the cover was intact and evidence of tampering was not observed. I then checked to see if I was able to pull the shifter out of park. Initially, I was unable to, but after a few tries and a little force, I was able to pull the shifter out of park (no keys in ignition, no brake compression, vehicle off) and the van began to roll. Our driveway is somewhat sloped. I replicated this procedure several times: a little force and a little wiggle and clunk, the shifter released and the van rolled. I discovered there was a recall for this very problem on 2010 Sienna’s (the federal safety agency Recall No.: 17V‑657). I entered the Sienna’s VIN number on the federal safety agency’s website and found no active recall for the VIN number entered. I contacted Toyota of North America (1‑800‑331‑4331) and chose to advocate and spoke to an agent and reported the problem. She was able to determine that the vehicle had been under the recall, but the van was “repaired” in 2020 which is the year we bought the van INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Jan 20, 2026 · Transmission · 120,000 miles · CO

The contact owns a 2017 Toyota Sienna. The contact stated that while starting the vehicle, reversing, and then while driving 20 MPH, there was an abnormal whining sound coming from the front of the vehicle. A dealer was contacted. The vehicle was taken to the dealer and was currently being diagnosed. The vehicle was not repaired. The contact related the failure to Technical Service Bulletin: TSB-0160-18 (Transaxle Whine Noise, Harsh Shift, MIL ON, or Reduced Power); however, the VIN was not included in the bulletin. The manufacturer was notified of the failure and referred the contact to the federal safety agency Hotline to report the failure. The failure mileage was 120,000.

Filed Sep 30, 2024 · Transmission · 110,000 miles · KS

The contact owns a 2017 Toyota Sienna. The contact stated while driving at an undisclosed speed, the contact became aware of a hard shift and a high-pitched whining sound while the transmission was shifting. The vehicle was taken to an independent mechanic where it was diagnosed with transmission failure. The contact was informed that the transmission needed to be replaced. The vehicle was not repaired. The manufacturer was made aware of the failure but provided no assistance. In addition, the contact was informed that the repair was not covered under recall. The failure mileage was approximately 110,000.

Filed Mar 17, 2023 · Body, Locks · CT

The contact owns a 2012 Toyota Sienna. The contact stated that the rear passenger side power sliding door cable broke. The driver-side power sliding door was malfunctioning. There was an abnormal clunking noise detected. The door failed to close with the automatic button. The contact had to manually close the door. There were no warning indicator lights illuminated. The vehicle was taken to the local dealer where it was diagnosed that the door needed to be replaced and was informed the repair coverage had expired. The vehicle was not repaired. The manufacturer was not contacted. The failure mileage was unknown. The contact stated that the failure was related to the federal safety agency Campaign Number: 16V858000 (Structure).

Filed Nov 7, 2022 · Steering · IL

The intermediate shaft makes a clunking noise when turning the steering wheel.

Filed Jul 20, 2020 · Steering · 62,000 miles · PA

The intermediate steering shaft started making a clunking sound when turning the wheel and driving a low speeds. Additionally, there is now play in the steering wheel. So much play that driving at highway speeds feels unsafe.