Standalone Game wheeled vehicle goes wild and flies off

I have been using UE4 for 7 months now. couple of days ago I moved some files to another hard drive. When I activate selected view port. my wheeled vehicle is fine and doing what its suppose to do. But when go in to Standalone Game the vehicle flips wildly and flies of into space. But if no solutions. I will re rig the vehicle to see if the problem still exists.