Truck won’t turn over, makes no sound, Gears shift without brake pedal

Truck won’t turn over, makes no sound, Gears shift without brake pedal I was moving my truck from one part of my yard to the other. As I put in park I heard a pop and then my truck died. It will not turn over but I can put it in the on position and listen to the radio. I am also able to shift gears without having the brake pedal pressed.