While backing up at working, My truck cut off on me. Here is what happened. I had the steering wheel hard to the right and was backing up when it just cut off. Moved the shifter into N then back into Reverse and the truck started back up, but would not move. So I put in Park and turned the key off then started it back up and the backed up in the parking place with no problem. I have had it a few times while backing up in the driveway but nothing like today. What the hell is causing this?