2021 Toyota Highlander

There is Powertrain - Transmission failure on my 2021 Highlander V6 8 speed with just over 50,000 miles. Toyota is aware of transmission failures with the Highlander family of vehicles equipped with the UA80 transmission. The failure with the UA80 transmission can cause a sudden power loss in traffic which escalates it to a safety issue. My Vehicle has been inspected by the Toyota dealership and confirmed to be well-maintained. Transmission failure confirmed by dealership and documents have been shared with Toyota Corporate (Toyota Motor North America). Toyota is refusing to take any responsibility, cover any cost associated, or do any recall, putting their consumers and others at risk.

NHTSA ID

11776300

Incident

Oct 13, 2026

The transmission started whistling around 66k miles. It was diagnosed by 3 different dealerships, including Toyota, as a transmission failure. It was diagnosed as a known issue with this year Highlander, with no fix on the market. I am having to pay $10k out of pocket because this is out of warranty by 6k miles. Highly dissappointed.

NHTSA ID

11775991

Incident

Sep 1, 2026

**Component:** The 8-speed automatic transmission (Aisin UA80F, AWD) failed internally. A Toyota dealer test-drove the vehicle on 10/09/2026 and verified the noise comes from transmission internals. The repair order states: "Internal transmission failure causing whining noise while driving/accelerating." **Safety risk:** The transmission is failing internally and has not yet failed completely; if it does while driving, it could cause a sudden loss of motive power. I am reporting it because the same failure mode is documented in Toyota service bulletin T-SB-0008-21 (front carrier assembly pinion shafts), but this transaxle — serial A4A20M 00395, built at TMMWV in December 2020 — is immediately outside the bulletin's affected range (A4A20L00101–A4A20L01824, November 2020). It failed identically, which suggests the November 2020 production change did not fully correct the defect. **Inspection:** A Toyota dealer confirmed the failure by test drive and inspection. Toyota (the manufacturer) has not inspected the vehicle. No police or insurance inspection. **Symptoms:** A whine at all speeds. No warning lamps or messages. No crash, injury, or fire.

NHTSA ID

11775774

Incident

Oct 9, 2026

I purchased my 2021 Toyota Highlander AWD brand new in March 2021. In May 2026, at approximately 120,000 miles, I began hearing a high-pitched whining noise coming from the transmission. The noise became louder as I accelerated. Toyota disregarded the noise and advise that it was normal due to the mileage of the vehicle In August 2026, I took the car back to perform an oil change and tire rotation and I mentioned once again the noise coming from the transmission, Once again the dealer told me that i was due to the mileage. I took the car in October 26 to perform oil change and tire rotation and I mentioned the noise again. The dealer then made an appointment to inspect the issue Toyota dealership technicians inspected my vehicle and diagnosed failing transmission bearings. Toyota confirmed that the transmission needs to be completely replaced. The estimated replacement cost is $9,500. I am concerned about the safety risk because a failing transmission can potentially cause loss of power, unexpected changes in vehicle movement, or difficulty accelerating while driving in traffic. I am concerned that the condition could worsen and create a dangerous situation for me, my passengers, and other drivers. The first symptom was a high-pitched whining noise that began in May 2026 at approximately 120,000

NHTSA ID

11775645

Incident

May 9, 2026

When driving I had to brake hard to avoid a collision. My daughter was riding in the front passenger seat. Both my daughter and myself were buckled in our seat belts. When I had to brake, her seat moved all the way to the front position and she was thrown forward towards the front windshield. There is an active recall for my car where the recliner assemblies in the second-row seats may not fully lock after seat back adjustment. This seems to be the exact same issue but we experienced this with the front passenger seat. I reported the issue to Toyota but my vehicle has not been inspected yet. I am having the rear recall fix completed in late November. The issue put my daughters safety at risk and was very alarming for both of us. There were no warning messages or symptoms of a problem with the seat.

NHTSA ID

11774559

Incident

Aug 18, 2026

My 2021 Toyota Highlander XLE began making a high-pitched whining noise when accelerating. When researching this noise, associated with the make, model, and year of my vehicle, it became apparent that the noise is associated with a manufacturer's defect in the [XXX]‑speed transmission (Toyota [XXX]). The cited notification states that the correction for this defect is a transmission replacement that is only covered by the 60,000 mile/5 Year warranty. There are three class-action lawsuits associated with this issue, and I wanted to document my incident in the event that my service appointment with [XXX] Toyota in [XXX], on 11/23/2026 indicates that my transmission is affected by the defect so many have experienced. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11774350

Incident

Oct 26, 2026

I recently purchased a 2021 Toyota Highlander Platinum. Within a few weeks from purchase, the transmission started making a whining noise. Upon further research, it was discovered that Toyota has been installing the UA80=F transmission in their vehicles, knowing full well that there are serious issues with this particular transmission. But yet they continued using this transmission. Someone needs to address this issue and hold their feet to the fire.

NHTSA ID

11772893

Incident

Oct 9, 2026

The contact owns a 2021 Toyota Highlander. The contact stated that while driving at slower speeds and attempting to park the vehicle, the vehicle unintendedly accelerated into a rail while the brake pedal was depressed. The vehicle was towed to a nearby Collision Center for the repair. The contact sustained injuries to the left leg, left hand, and left elbow. The contact sought medical attention for the injuries. The manufacturer was made aware of the failure by telephone. The failure mileage was approximately 150,000.

NHTSA ID

11772667

Incident

Sep 23, 2026

Mileage

150,000 mi

Some 2020 – 2026 model year Highlander and Highlander Hybrid vehicles may exhibit a water leak from the roof rack attachment clips. This may be caused by the sealant in the roof channel obstructing the proper seating position for the clip gasket.

Some 2020 – 2024 model year Highlander and Highlander Hybrid vehicles may exhibit a condition in which the air conditioner does not cool due to a leak and/or corrosion in the rear underbody air conditioner tube and accessory assembly. The anti-corrosion material has been updated to reduce the possibility of this condition.

OBSOLETE NOTICE January 30, 2026: This bulletin is now obsolete. Please see T-SB-0001-26.

Some 2018 – 2024 model year Toyota vehicles equipped with a Premium Audio with Dynamic Navigation System require a Special Service Tool (SST) USB flash drive to update the map, points of interest, and system software.

Some 2005 – 2026 Toyota vehicles that have undergone water intrusion may exhibit a condition in which a musty odor is present. Follow the procedures in this bulletin to remediate the odor and address this condition. The purpose of this Service Bulletin is to provide general guidelines and procedures for odor remediation. This Service Bulletin provides a guide on how to prepare and treat the interior of the vehicle for odor remediation. Refer to the applicable model and model year Repair Manual and the EPA (Environmental Protection Agency) website for the most up-to-date safety and precautionary guidelines.

Some 2020 – 2023 model year Highlander and Highlander Hybrid vehicles may exhibit a condition in which the Power Back Door (PBD) will not open or close and/or stops moving while opening or closing. A modified PBD unit assembly is available to address these conditions.