Not exactly sure how it started to happen. Meaning there was a powertrain malfunction so my Ford computer tells me, which caused the vehicle to not restart and in addition to it not restarting, the vehicle also didn't have brakes, so it simply rolled backwards without any control until I hit a tree to stop me. On the way down, I also hit the bumper and damaged it and also hit the driver's side mirror on a rock on the way down.