2021 Toyota Highlander: sudden loss of power

Filed Nov 6, 2026 · Transmission · IA

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.

Filed Nov 4, 2026 · Transmission · IL

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

Filed Sep 9, 2026 · Transmission · IN

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.

Filed Sep 8, 2026 · Transmission · TX

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.

Filed Sep 6, 2026 · Transmission · TX

**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 the federal safety agency'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.

Filed Aug 21, 2026 · Transmission · UT

Bought my 2021 Toyota Highlander XLE AWD 3 years ago due to supposed safety and reliability. Transmission went out right after warranty at 64,000 miles. Was not made aware that this is a common issue. Vehicle hard shifted and suddenly lost power when driving home with my 4 year old while making a left turn, and we were almost hit by oncoming traffic. Have not had prior issues in the past to suspect this would happen, so it was very sudden and unexpected. There has been no recalls or awareness for this which could have seriously injured my child and I. Went to take it to the closest mechanic right away to troubleshoot since the vehicle was not throwing any codes.

Filed Aug 19, 2026 · Transmission · WI

At around 75000 miles (less than 5 year old vehicle) the transmission exhibited a noticeable whine. After further research I presented the vehicle to the local Toyota dealer service department. An active technical service bulletin T-SB-0008-21 that describes a manufacturing defect with the front carrier assembly pinion shaft (essentially a catastrophic transmission failure) was matched to the symptom the vehicle was exhibiting. Further, my transmission serial number is directly within the affected production defect list. Failure to replace this transmission at significant cost (should not normally be routine maintenance on a highway driven vehicle at this age and mileage) could result in total loss of power and control causing the potential for a severe traffic hazard or accident.

Filed Jun 25, 2026 · Driver assistance · AZ

2021 Toyota Highlander UA80 transmission failed at 100,000 miles. Codes P2808, P0741. Matches Toyota TSB-0160-18 and T-SB-0008-21. Dealer Alexander Toyota and TMS Brand Engagement denied goodwill. TMS rep stated "TSBs don't matter" despite pending class action Pallaya v Toyota, Case 2:25-cv-10458, which cites these TSBs as proof Toyota knew of defect. Toyota refusing to honor documented defect. Transmission slip/loss of power is safety issue. Request investigation.

Filed Jun 17, 2026 · Transmission · KY

The transmission in my 2021 Toyota Highlander began producing a whining noise during acceleration between approximately 15-50 mph at around 80,000 miles. The noise stops when the accelerator is released and has progressively become louder. The vehicle was inspected by a Toyota dealership. I was informed that the condition is a known issue affecting some Toyota vehicles, but no repair was offered because the vehicle is outside the 5-year/60,000-mile powertrain warranty. There are currently no warning lights or diagnostic trouble codes. I am concerned that the transmission may fail while driving, resulting in loss of power or propulsion and creating a safety risk for myself and other motorists. The vehicle remains available for inspection.

Filed May 26, 2026 · Transmission · CA

I own a 2021 Toyota Highlander with approximately 100,500 miles. The vehicle has developed a noticeable whining noise coming from the transmission/drivetrain area that continues to worsen over time. The noise is most noticeable during acceleration and while driving at highway speeds. I brought the vehicle to Toyota for inspection and was informed that the issue is related to the transmission. However, Toyota denied repair assistance because the vehicle is outside the powertrain warranty period. After researching the issue, I discovered multiple similar complaints involving 2021 Toyota Highlanders equipped with the UA80 transmission, including Toyota Technical Service Bulletin T-SB-0008-21 regarding “Whine or Grind Noise From the Transmission.” The symptoms described in the bulletin closely match the symptoms my vehicle is experiencing. Toyota appears aware of this transmission-related issue, yet many owners outside the warranty period are being denied coverage despite similar failures and complaints. I am concerned this may represent a broader transmission defect that could lead to premature transmission failure, unsafe driving conditions, hesitation, loss of power, or expensive repairs for consumers. I believe this issue should be investigated further by the federal safety agency due to the growing number of similar complaints involving whining transmission noises and transmission failures in Toyota Highlander vehicles. At this time, the vehicle has not yet experienced a complete transmission failure, but the condition is worsening and raises significant concerns regarding reliability and safety.

Filed May 21, 2026 · Transmission · AZ

My car start with a noise and just lost power in the middle of the road causing almost an accident. This was caused due to the manufacture issue for the transmissions with my car model and brand.

Filed May 18, 2026 · Transmission · CA

What component or system failed or malfunctioned, and is it available for inspection upon request? - Transmission is in the process of failing. Yes it is available for inspection. How was your safety or the safety of others put at risk? - Loss of power train while driving could put the operator and the public at risk. Has the problem been reproduced or confirmed by a dealer or independent service center? - Yes, I've been told by two separate Toyota dealers that my transmission needs to be replaced. Has the vehicle or component been inspected by the manufacturer, police, insurance representatives or others? - Yes. Were there any warning lamps, messages or other symptoms of the problem prior to the failure, and when did they first appear? - No.