2021 TOYOTA HIGHLANDER Complaints

**Component/System:** Automatic Transmission — 8-speed (UA80E/UA80F), Toyota Highlander **Description of the problem:** My 2021 Toyota Highlander (approximately 116,000 miles) has developed a high-pitched whining noise a while ago, that occurs during acceleration, consistent with the symptom described in Toyota's own Technical Service Bulletin T-SB-0008-21 (issued Feb 9, 2021) for whine/grind noise in the transmission on this model. The vehicle has not yet been formally diagnosed by a dealer or independent shop as of this filing; I am submitting this report proactively given the volume of documented failures in this transmission platform and to add to NHTSA's record before the condition potentially worsens. I am aware, through Toyota's own TSB and multiple pending class-action lawsuits (including Pallaya v. Toyota Motor Sales U.S.A., Case No. 2:25-cv-10613, C.D. Cal., and LeBoutheller v. Toyota, Case No. 4:25-cv-01389, E.D. Tex.), that this transmission (UA80E/UA80F, used in 2017-present Highlander and related Toyota/Lexus models) has a documented pattern of premature failure nationwide, often presenting first as this same whining noise, and in a number of owner-reported cases progressing to sudden power loss, shifting into neutral, or stalling — creating a serious safety risk to occupants and other drivers, particularly at highway speeds.

At 57,000 miles the dealership says the transmission must be replaced. Toyota refused to replace it under warranty because they stated it wasn't serviced at Toyota consistently. There isnt a service for the transmission under 100k miles. This is a known issue with this transmission and they act oblivious to this issue.

On August 24, 2026, my vehicle was parked, turned off, and locked for more than 6 hours in a parking lot. Without warning, the vehicle experienced a spontaneous thermal event/self combustion. The fire and thermal damage were entirely localized to the dashboard area inside the passenger cabin. The engine compartment, battery area and front mechanical components remained completely unaffected by the fire. The vehicle was off, motor was cold and car was closed and parked for about 6 hours when this incident occurred.

The transmission whining started 70,000 miles and it is progressively gotten worse, there has been some sudden shifting at times. The manufacturer has known about this 8 speed transmission. Problem since 2017 and they haven’t done anything to improve it. Isn’t is something that the warranty only covers the drivetrain and. Transmission till 60,000. And know they are telling us that we have to pay anywhere from $7,000-$12,000 to,have it replaced. We have taken it to the Toyota dealership Thayer Toyota in bowling green,oh and they checked it out. And said that the front part of the transmission is ok it’s but the rear differential is the one that is going bad. We are hoping that there will an investigation on this UA80 transmission to see how many of the toyota models that have this transmission in it, have been reported and if any after the 60,000mile they have covered to be repaired at there cost. We understand that there is a CLASS ACTION LAWSUIT against this transmission. We would appreciate any help that you can get us. We can be contacted at [XXX] or phone number [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

While driving and applying the brakes to come to a complete stop at low speed (approximately 5–15 mph), the vehicle intermittently loses brake responsiveness for a brief moment during the transition from regenerative braking to hydraulic (friction) braking. This causes the vehicle to lurch forward unexpectedly before the brakes fully re-engage. The issue is intermittent and unpredictable, occurring most often when coming to a stop at slow speed, which makes it difficult to anticipate and compensate for. This has happened more than a few times now, most latest, On XXX, this occurred while approaching a stop at traffic light and it felt that the vehicle nearly made contact with the vehicle ahead of me. I brought the vehicle to Elgin Toyota in [XXX] , in 2025 to report this issue. The service department test drove the vehicle but was unable to reproduce the symptom and did not perform any repair. I have since learned that Toyota issued Technical Service Bulletin T-SB-0059-23, "Hybrid Regenerative Brake Transition Feeling Improvement," dated XXX, which describes this exact symptom in 2020–2022 Toyota Highlander and Highlander Hybrid vehicles. I am filing this report because I believe this is a safety-related braking defect, particularly at low-speed stops, that creates a real risk of a rear-end collision. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

1. The car makes a squeaky sound when I accelerate. The faster I go the louder the noise becomes. I took the car to the Toyota dealership and was told that the transmission needs to be replaced. The car is only 5 years old. I checked online and noticed a lot of other people are also complaining about the same issue with their 2021 Toyota Highlander. 2. While driving on the Turnpike a few months ago, the driver side front door suddenly popped open on me. I had to hold it with my left hand, switched lane to pull safely to the shoulder lane in order to close it. The door was completely closed prior to this incident. When that happened, I was already driving on the road for over 1 hour. There was no previous signal that it was opened. It just popped open out of nowhere.

Toyota has known that the UA80 transmissions are faulty & they have not issued a recall. Mine failed at 60,500 miles just outside of the warranty period. I paid over $5,000 to have it replaced & the dealer confirmed that it required replacement due to a faulty transmission assembly. Toyota refuses to issue a recall or cover full costs for replacement.

It's about the problem with the automatic transmission UA80 already has the buzz That many customers are complaining sometimes it has jerks too.

The car's transmission is failing. •The "Whine of Death": The most common early warning sign is a high-pitched, airplane-like whining noise that rises in pitch with vehicle speed/engine RPM, especially once the transmission reaches operating temperature. •Technical Service Bulletins (TSBs): Toyota has issued internal bulletins (such as T-SB-0008-21 and related updates) addressing abnormal transmission noises and replacement protocols for affected V6 models. •No Formal Safety Recall (as of mid-2026): While the issue has spurred class-action lawsuits and high NHTSA complaint volumes, there has not been a mandatory safety recall for widespread replacement, leaving post-warranty owners to rely on goodwill assistance or third-party warranties.

At 66,000 miles the transmission on my 2021 toyota highlander is failing. This is a known issue with these transmissions and toyota is actively working against people to help get the parts replaced at their cost.