2021 Toyota Highlander power train problems

“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.”

“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.”

“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.”

“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.”

“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.”

“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.”