2021 Toyota Highlander

My 2021 Toyota Highlander equipped with the UA80 transmission developed a whining/grinding noise under acceleration around 73,000 miles. Toyota diagnosed internal transmission failure and recommended full replacement costing approximately $9,000. Toyota issued TSB T-SB-0008-21 acknowledging defects involving the front carrier assembly pinion shafts in these transmissions. This defect creates a potential safety hazard due to possible loss of power or drivability during highway operation. I am requesting that NHTSA investigate the widespread transmission failures affecting 2021 Highlanders and related Toyota vehicles.

I noticed transmission whining shortly after purchasing on 3/12/24. Odometer reading at purchase 62,347. I justified whining to myself as luck of the draw. Until a few months ago I started hearing grinding noise coming from the transmission. Had transmission diagnosed at Lancaster Toyota on 4/22/2026. Approximate odometer reading, 78,700. Was told that a replacement transmission was needed. Cost 9,526.17 No warning lamps or messages appeared. Transmission type UA80F SN A4A20J O 4195

Transmission. My 2021 Toyota Highlander with approximately 94,500 miles developed a consistent whining noise during acceleration. The issue occurs daily during normal driving and appears to be worsening. A Toyota dealership diagnosed the problem and confirmed the noise is coming from the transmission and that the transmission requires replacement. This appears to be a premature failure of a major drivetrain component. The condition could lead to loss of power or transmission failure while driving, creating a potential safety risk. There was no prior warning, and the vehicle has been properly maintained.

2021 Toyota Highalnder UA80F Transmission Whine / Known Defect - Potential for Sudden Failure I own a 2021 Toyota Highlander Platinum V6 AWD (UA80F 8-speed automatic transmisstion) purchased in July 2021. Current milage is 78k. Starting 3 days ago I noticed a faint whine noise coming from the transmission. The pitch changes with speed and when the throttle is depressed (It's louder under load/acceleration). This matches the exact symptoms described in Toyota TSB T-SB-0008-21 for whine/grind noise caused by the front carrier assembly pinion shaft issues in 2021 Highlanders with UA80 transmissions. On April 27, I went to a Toyota dealer to confirm the source of the noise and diagnose. As per their diagnosis report "Tech took vehicle on road test to duplicate concern, after confirming complaint vehicle was then lifted up and inspected while under a load, tech as able to isolate noise to transmission at this time, fluid level and condition was inspected to ensure there were no signs of shavings or discoloration and after inspection tech found nothing abnormal during fluid level check. Tech then ran a health check to ensure there were no DTC present related to transmission concern and found no DTC present. Recommend replacing transmission and torque converter at this time". They provided a quote of $9,392. This condition represents a safety concern because the internal wear can progress to harsher shifting, loss of power, limp mode, or complete transmission failure while driving, potentially causing a crash or stranding the vehicle in traffic. I have audio/vehicle recordings of the whine and service records showing regular Toyota dealer maintenance. I am requesting the the NHTSA investigate this ongoing UA80 transmission issue as it appears to be a known manufacturing or design defect tat continues beyond the narrow TSB applicability and warranty limits.

The contact owns a 2021 Toyota Highlander. The contact stated that there was an abnormal winding sound coming from the vehicle while accelerating. There were no warning lights illuminated. The vehicle was taken to the local dealer, where it was diagnosed with transmission failure. The vehicle was not repaired. The contact called a transmission shop and was informed that the part to repair the vehicle was on back order. The manufacturer was contacted, opened a case, and referred to the NHTSA Hotline to report the failure. The failure mileage was approximately 106,000.