2021 Toyota Highlander Powertrain (other) Problems

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

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 an undisclosed speed, there was a loud high-pitched whining sound coming from the vehicle. The contact stated that the vehicle hesitated while accelerating and the transmission was shifting rough. The contact stated that the vehicle had experienced an internal transmission failure. The manufacturer was notified of the failure. A local dealer was contacted and associated the failure with Toyota Technical Service Bulletin: 0008-21. The contact stated that a diagnostic test was scheduled. The failure mileage was 70,100.

NHTSA ID

11770086

Incident

Jul 1, 2026

Mileage

70,100 mi

Noticed a whine noise slowly progressing over a couple of weeks. Researched the sound and took it for diagnostic eval. with Holman Toyota in Mt. Laurel, NJ on 10/3/2026. As suspected, the transmission is failing. Mechanic documented via video the fluid sample containing suspended metallic particles with discoloration and burnt odor. They also verified the whining sound coming from the transmission. This is a known failure for the 2021 highlander with a TSB bulletin. Although they have yet to place a recall. There were no warning messages. The complete failure of a transmission while driving could cause sudden immobilization and most certainly result in an a motor vehicle accident. The vehicle has under 54,000 miles and is about 10 weeks outside the warranty.

NHTSA ID

11769405

Incident

Sep 20, 2026

65K miles on the vehicle and have started to get a whining noise from the transmission during acceleration. UA80F transmission installed with multiple class action lawsuits against Toyota for this issue as it leads to catastrophic failure with high replacement cost. Stopped driving the vehicle and looking into transmission replacement options. Toyota needs to be held liable for mechanical defects.

NHTSA ID

11768883

Incident

Sep 1, 2026

We bought a 2021 Toyota Tacoma Platinum in November 2020. In February 2021, Toyota issued a Technical Service Bulletin T-SB-0008-21. The bulletin say transmissions may exhibit a whine or grind noise from the transmission. This condition may be caused by an issue with the front carrier assembly pinion shafts. This bulletin says repair is covered under the Toyota Powertrain Warranty. This warranty is in effect for 60 months or 60,000 miles, whichever occurs first, from the vehicle’s in-service date. Our transmission began making this noise around 75k miles, outside the warrant. Toyota knew about this problem over 5 years ago and did not take action to recall it. Now this repair is going to cost between $9,000 to $12,000 out of pocket. I cannot afford this repair. I have uploaded the bulletin from Toyota.

NHTSA ID

11768861

Incident

Oct 4, 2026

Transmission jerks and shutters at low speeds on acceleration 0-20 mph. Vehicle has low milage 25518 at which time the dealer re-flashed the software on july 29th 2026.The vehicle was fine for two months , then on October 3rd the problem came back on October 3rd 2026 hesitating like a premature upshift from 1st to 2nd gear at 5 mph with a shutter. The current mileage is 28000 on the vehicle and the problem is intermittent.

NHTSA ID

11768772

Incident

Oct 3, 2026

Transmission developed a whine at 61k miles. Needed to be replaced.

NHTSA ID

11766567

Incident

Sep 30, 2025

Toyota refuses to issue a recall for a well known issue with the UA80 transmission that fails around 5 years on many Highlanders. I follow [XXX] and there are countless posts about this issue. Mine failed at one month before my warranty was up and replacement was covered but it was replaced with the same transmission which I assume will also fail after 5 years or another 50,000 miles. There is a service bulletin for repair from Toyota so they're half admitting the issue but there needs to be a recall and a revision to the UA80 transmission to make them safer. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11766307

Incident

Jul 15, 2026

In my Toyota Highlander 2021 XLE model ,on 9/18 I hear a whinning noise when gas pedals is pressed. Took it to the Toyota TriCounty dealer in Limrick,PA for diagnosis. It was reported it is due to a transmission issue and it would cost around 10,600$ to repair. I haave been taking this vechile to same dealer to servie for last 5 years and this problem did not surface. I was told the car can be driven but would the car would stop when the transmission actually fails. Opened a case

NHTSA ID

11765895

Incident

Sep 18, 2026

Tech: SCOTT RICHART test drove vehicle performed inspection. Noise hear is coming from transmission internally. condition present is similar to condition described in T-SB-0008-21 for whine noise from transmission. Transmission would need replaced to remedy the noise. Vehicle is out of warranty, DOFU is 04/14/21. Transmission is not in the serial number range described in the TSB. Transmission serial # is A3A21C08858. QUOTED $8574.50 TO REPLACE TRANSMISSION WITH REMANUFACTURED TOYOTA TRANSMISSION.

NHTSA ID

11764197

Incident

Sep 14, 2026

Transmission Failure Yes TSB No Warning Lights

NHTSA ID

11764003

Incident

Sep 13, 2026

There is an unknown whine coming from the transmission when pressing on the throttle. It loud and high pitched.

NHTSA ID

11763567

Incident

Sep 11, 2025

Leadcar Toyota LaCrosse WI has diagnosed and reported that the transmission needs to be replaced. Pertains to Service Bulletin T-SB-0008-21 the pinion shaft bearing defect. The major powertrain component is failing prematurely. Cost to repair is over $9,000 as it is out of warranty. We purchased the vehicle at 67,550 miles on 3/29/2025. Since we never owned a Toyota before we thought the whining of the transmission was unique to that vehicle. Once we heard about the service bulletin we took it in to get diagnosed.

NHTSA ID

11763402

Incident

Aug 10, 2026

Transmission failure at 80,000 miles

NHTSA ID

11763132

Incident

Sep 9, 2026

transmission has failed. Toyota states: Toyota Technical Service Bulletin T-SB-0008-21 addresses a whining or grinding noise in select 2021 Toyota vehicles equipped with UA80E orUA80F automatic transmissions caused by a defect in the front carrier assembly pinion shafts. Yes it can be available for inspection. This can be repaired with a $12,000 new transmission. * Sudden loss of acceleration: You may press the gas and the vehicle doesn’t accelerate normally. This is particularly dangerous when merging onto a highway, crossing an intersection, or passing. How this toyota highlander is putting safety at risk: * Unexpected shifting or jerking: A failing transmission can slam into gear, hesitate, or shift unpredictably, potentially causing loss of control. * Loss of drive: The transmission may suddenly stop transferring power to the wheels. You could be unable to move forward even though the engine is running. * Getting stuck in a gear: If it goes into a “limp” or failsafe mode, the vehicle may be restricted to a single gear and have very limited acceleration. * Loss of power while already moving: If the transmission disengages unexpectedly, you can lose the ability to accelerate out of a dangerous situation. * Difficulty maintaining speed: On a highway or uphill, a failing transmission may suddenly stop providing adequate power. * Transmission fluid leaks: A significant leak can cause the transmission to lose lubrication and worsen rapidly. Depending on where fluid goes, it can also create other mechanical problems. * Unexpected engine RPM increases: The engine can rev very high without the Highlander gaining speed (“slipping”), which can leave you unexpectedly slow in traffic. * Being stranded in traffic: A complete failure can leave the vehicle immobile, creating a collision hazard if you’re stopped in a travel lane or on a shoulder. unknown if it has been inspected by anyone. There is no warning lights. Then only way you know is by a high whining sound.

NHTSA ID

11763069

Incident

Aug 24, 2026

The 8 speed automatic transmission (UA80E) in my 2021 Toyota Highlander Limited V6 FWD failed at 75,491 miles. The failure presented as a loud whining noise during acceleration between 30 and 40 mph. A Toyota dealership diagnosed complete transmission failure requiring full replacement of the transaxle assembly at a cost of $8,144.45 (repair order dated August 14, 2026). The dealership service manager confirmed in writing that the failure appears consistent with Toyota TSB T-SB-0008-21, issued February 9, 2021, which documented whine and grind failures of the front carrier assembly pinion shafts in this transmission family. My transmission was built in June 2021, after the serial range covered by that bulletin, and failed the same way, indicating the defect was not confined to the bulletin's production range. This transmission is the subject of multiple pending federal class action lawsuits alleging premature failure. A transmission failure of this type can result in sudden loss of power while driving, which is a safety hazard. The vehicle was purchased new from a Toyota dealership in July 2021, was maintained normally, and was never used under severe service conditions. The problem has been confirmed by the dealer. The vehicle and failed component are available for inspection and the vehicle remains at the dealership.

NHTSA ID

11762799

Incident

Aug 14, 2026

**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.

NHTSA ID

11762480

Incident

Jul 1, 2026

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.

NHTSA ID

11761897

Incident

Aug 19, 2026

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)

NHTSA ID

11761620

Incident

May 30, 2026

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.

NHTSA ID

11761538

Incident

Aug 19, 2026