Differential Unit problems of the 2020 Toyota Highlander

The contact owns a 2020 Toyota Highlander. The contact stated while driving at various speeds and accelerating, the vehicle made an abnormal buzzing and clunking sound. The vehicle was taken to the dealer several times. The dealer repaired the brake pedal and an axle; however, the failure progressively became worse. The vehicle was taken back to the dealer, where the rear differential was repaired; however, the failure persisted. The vehicle was taken back to the dealer, where it was diagnosed and determined that the transmission needed to be replaced; however, the part was not available. The vehicle was not repaired. The manufacturer was notified of the failure and a case was opened. The failure mileage was approximately 59,000.