The contact owns a 2020 Ford Expedition. The contact stated the transmission was slipping while driving at an undisclosed speed. The contact stated that on one occasion, while her daughter was driving 60 MPH, the transmission started slipping and the vehicle failed to accelerate above 60 MPH. There were no warning lights illuminated. The contact stated that the failure was related to TSB: 23-2120. The vehicle was taken to the local dealer, who was unable to duplicate the failure. The vehicle was not diagnosed or repaired. The dealer informed the contact that the vehicle needed to be test-driven. The manufacturer was contacted and opened a case. The failure mileage was approximately 85,000.