2021 Toyota Highlander

I own a 2021 Toyota Highlander with approximately 127k miles. The vehicle has developed a noticeable whining/whirring noise during acceleration. The noise appears to originate from the drivetrain/transmission area and has become increasingly noticeable over time. The condition occurs every-time during acceleration and is present under normal driving conditions. I am concerned that this may indicate a transmission or drivetrain-related issue that could affect vehicle reliability and safety. I have found reports from other 2021 Toyota Highlander owners describing similar symptoms involving whining noises during acceleration. The vehicle has been inspected by a Toyota dealership. And is certified through Toyota. The vehicles was bought new from the Toyota dealership and has had all service done through Toyota. I am submitting this complaint so NHTSA can evaluate whether this condition is part of a broader pattern affecting similar vehicles as a defect in the original transmission built in the SUV.

I own a 2021 Toyota Highlander with approximately 93,000 miles. The vehicle developed transmission symptoms including whining noise. A Toyota dealer diagnosed internal transmission failure and recommended complete transmission replacement at a cost of approximately $9786.31. Toyota declined repair assistance. I am concerned because a transmission failure at this mileage is unexpected and appears similar to other owner complaints involving the 2021 Toyota Highlander transmission.

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.

Right after the manufacture warranty of 60K miles, the car began to make a humming noise. I took the car into the dealership with 65K miles on 13 Jun 2026, and the Toyota dealership stated that the humming is caused by the transmission and we will need to replace the entire transmission. The cost would be $9,447.29. This issue is known by Toyota and Toyota put out Toyota Service Bulletin (T-SB-008-21) but failed to issue recall for this defective transmission.

On two separate occasions I was traveling approx. five to ten miles an hours and had to change lanes. Traffic was heavy and I had to accelerate quickly to do the lane change. The vehicle engine started to rev high and I was barely moving. It was like the transmission didn't know what to do. I had to let my foot completely off the gas for fearing I was going to blow something up. I advised Toyota On Nicholasville several times and they totally ignored me. Also occasionally the transmission will make a clunking noise when shifting in reverse. While this isn't as much of a safety concern as needing your vehicle to respond in traffic and it doesn't. It's very difficult to get Toyota dealers even to document what your concerns are. The way they see it, if wasn't documented, then it didn't happen. The transmission in this vehicle is not safe. You can't rely on the transmission to respond if you are put in a dangerous situation.

My vehicle has 67,100 miles. A whining/whistling noise recently started and the dealer has diagnosed that a new transmission is needed at a cost of $6,000-$8,000 and it is out of warranty. Researching this shows that this is a known manufacturing defect referred to under T-SB-0008-21. I am concerned that my transmission will fail while I am operating the vehicle.