I have a 8 HP Craftsman Rear Tine tiller 917.299680 and the ground drive shifter is jammed. When the tiller was parked it was driven into the barn, but now the trans won't shift. The drive pulley seems to be in neutral (spins freely by hand) but the drive wheels are locked. Just one time while spinning the drive pulley by hand the wheels turned forward like they were in high forward, but now they are jammed.