2021 Toyota Highlander Powertrain & Transmission Problems

My automatic transmission failed per the dealership and is just outside of the warranty but is considered a premature failure based on the expected life of the vehicle.

A whining noise was observed at around 78k miles. Brought to the dealer and they indicated parts in the transmission are failing and it requires replacement. They said this has been happening more frequently on 2021 Highlanders (also see T-SB-0008-21). It's also a well-documented issue online. My contact with Toyota was that they did not intend to cover any repairs as the vehicle is out of warranty, even though it's not an isolated issue. They would not disclose how many vehicles have reported this issue. I believe it has reached safety recall-level.

Transmission has failed as have many others of the same year make and model without acknowledgement of a manufacturer defect

My 2021 Toyota Highlander was my first car I purchased that I saved up for and has had a sudden issue accrue with a winning sound out of now where. I took it to the dealer ship and they told me I need a new transmission. My vechile only has 73k miles and I noticed this sound is getting worst and worst. I don’t know what to do so I turned to the internet and I was blow away to see how many people have this same issue with the same year and it’s been happing to so many people. I am a father of a special needs child and I sport my family on my own I can not afford to replace this and they won’t do anything for me. I beg anyone that reads this to please help us out cause this is not fair they we pay our hard earned money to get hit with this unexpected issues that they obviously know about but want do anything cause it will ruin there rep.

Transmission failure @110,000miles and a $9000.00 replacement cost. Service advisor at Toyota Dealership indicated they have seen other similar failures on this Highlander Platinum Model at their dealership but unit is out of warranty by a few thousand miles

The transmission began making a wheezing sound. The dealership looked at the vehicle and determined it needed a new transmission. This is a known problem. Toyota issued a service bulletin on the issue in February 2021. I purchased the vehicle a few months after that. T-SB-0008-21

During acceleration above 25 mph a noticeable whining sound is heard from the transmission. When not acceleration the sound goes away. The vehicle only has 72300 miles

The contact owns a 2021 Toyota Highlander. The contact stated that while driving at an undisclosed speed, there was a whining sound coming from the vehicle. There was no warning light illuminated. The vehicle was taken to the dealer, where it was diagnosed with transmission failure. The dealer stated that the transmission needed to be replaced. The vehicle was repaired. After the vehicle was parked and turned off, there was transmission fluid leaking from the vehicle. There was no warning light illuminated. The vehicle was taken back to the dealer, where it was diagnosed and determined that the head gasket had failed and needed to be replaced. The vehicle was repaired. The contact then noticed fluid leaking from the transfer case while the vehicle was parked and turned off. The vehicle was taken back to the dealer, where it was diagnosed and determined that the transfer case had failed and needed to be replaced. The vehicle was not repaired. The manufacturer was made aware of the failure. The approximate failure mileage was 74,700.

My vehicle is experiencing a transmission safety issue that has been diagnosed by the authorized Toyota dealer service center (Toyota of Scranton). During my most recent service visit on 3/2/26, the dealer reported that the transmission is “failing and whining” and recommended full transmission replacement. This condition creates unsafe driving behavior, including abnormal whining noise during acceleration and the concern for sudden transmission failure while driving. The Highlander started exhibiting issues with the transmission within the past 7 days. This issue appears consistent with the known transmission defect referenced in Toyota Technical Service Bulletin T‑SB‑0008‑21, which addresses whining and grinding noises caused by internal transmission component failure in 2021 model‑year vehicles equipped with UA80-series transmissions. Multiple independent reports indicate that this condition can worsen and may lead to loss of power or drivability while the vehicle is in motion. For safety reasons, I am submitting this complaint so the issue can be evaluated as part of any ongoing or future defect investigations. I am concerned about the potential risk of transmission failure while driving, which could increase the chance of a crash.

The contact owns a 2021 Toyota Highlander. The contact stated that the vehicle experienced transmission failure while driving. There was an abnormal whining sound coming from the vehicle while accelerating, and the sound increased in volume while driving. There was no warning light illuminated. The vehicle was taken to the local dealer, where it was diagnosed with an internal transmission failure. The vehicle was not repaired. The manufacturer was notified of the failure, but no assistance was provided. The failure mileage was approximately 55,803.

The contact owns a 2021 Toyota Highlander. The contact stated that while driving at an undisclosed speed, there was an abnormal whining sound coming from the transmission. The contact was concerned about the sound and contacted a dealer. The vehicle was driven to the dealer and was diagnosed with transmission failure. The vehicle was not repaired. The manufacturer was notified of the failure. The failure mileage was 60,347.

I am reaching out regarding our 2021 Toyota Highlander which currently has $65 K miles and is just out of warranty. Recently we noticed a wining noise during acceleration. We took the vehicle to the dealer who told us that the transmission will need to be REPLACED. $9500 repair. This is a known issue with Toyota and they will not work with us on this. We are stuck! No customer goodwill! Thank you!

I purchased my brand new Highlander on January 31, 2021 and was told today that I need a transmission replacement. My vehicle started about two month ago with a whining sound while accelerating. My vehicle currently has 78,000 miles and is out of the extended warranty of 60,000/5 year. I learned that Toyota released a bulletin on February 9, 2021 stating transmission issues for particular Toyota models, the Highlander being one. After researching the issue, there are several stories of Highlander owners who are experiencing the same issue. It’s a shame that they knew of the problem in February 2021 and with the transmission replacements on vehicles less than 5 years old and haven’t issued a formal recall for this known defect.

The vehicle experienced a transmission failure at approximately 62,000 miles, which required a transmission replacement. Toyota replaced the transmission with a rebuilt transmission. Immediately after the repair, the vehicle began experiencing multiple issues that were not present prior to the repair. The vehicle initially would not reverse, and the battery was drained shortly after the repair was completed. Following the repair, the vehicle has continued to experience ongoing electrical malfunctions, including dashboard warning lights, system alerts, and dash lights flashing during remote start. The vehicle has also developed a rattling noise underneath the vehicle. The exact failed component has not been clearly identified. The dealership has provided changing diagnoses and has not provided written diagnostic documentation despite requests. The vehicle has been inspected by the dealership multiple times; however, the issues have not been resolved. During a recent diagnostic, the dealership stated that the catalytic converter is now the issue, but this does not address the ongoing electrical problems. These issues raise safety concerns due to unpredictable vehicle behavior and potential failure of critical systems while driving. Warning lights and system errors began appearing after the transmission repair and have continued since that time. The vehicle is available for inspection upon request.

Toyota is asking me to pay for a brand new transmission replacement in my car that is only 5 years old, 74,000 miles on it. The cost is $10,000. How is it possible a brand new vehicle is needing this? I have read a lot of reviews that Toyota is knowingly using the transmission type that they even had to recall on earlier models. Why are they still making vehicles using this type of transmission when it continues to need total transmission replacement so early on? And Offer zero assistance. We bought Toyota because we thought it was the best. I will never buy Toyota again, this is a huge cost for a young family with a teachers salary.

Transmission has started to whine, my understanding is this is common for the transmission I have. I have had this verified by 2 different garages. There are no engine lights showing. The noise started around 90K.

I had the 60,000 mile service on February 2,2026 and after the service was completed I left the dealership and got on the freeway to go home. I heard a whining noise and immediately turned around and took it back to the dealer. I took the mechanic who worked on my car for a drive and he was able to hear the winding noise and we returned to the dealership. It took the mechanic three hours to come to the conclusion that I needed a new transmission. They still have my car and I have not heard anything about coverage or when it will be done.

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.

The transmission in my 2021 Toyota Highlander began making a loud whining/whirring noise that increases with vehicle speed. The vehicle was inspected by a Toyota dealership, and I was told the transmission has failed and needs to be replaced. Toyota stated the repair would be out of pocket, despite the vehicle’s age and proper maintenance. There were no warning lights prior to the failure. This condition affects drivability and raises safety concerns, including the risk of sudden transmission failure or loss of power while driving, especially at highway speeds. I believe this is a premature transmission defect and am reporting it for investigation.

Known transmission failure.whining noise when accelerating. T-SB-0008-21