The contact owns a 2018 Ford F-150. The contact stated while driving downhill at approximately 45 MPH, the transmission unexpectedly downshifted to first gear, causing the RPMs to elevate abnormally, and the vehicle decelerated unintendedly. Additionally, it was discovered that the vehicle would only drive uphill while using manual transmission mode and could not drive uphill in automatic transmission mode. The contact stated that later, the transmission malfunction wrench was displayed. The vehicle was towed the local dealer who discovered metal shavings inside the transmission fluid and advised the contact that the transmission needed to be replaced. The vehicle was not yet repaired. The manufacturer was notified of the failure, but no assistance was offered. The failure mileage was 100,000.