My Scotts/John Deere Model L1742 lawn tractor won't engage gears and won't move. The motor runs fine, the blade engages, but not the drive. The belt is not broken and moves, but the rear pully isn't turning. I can turn it by hand but the belt doesn't turn it.

Hi,
Have a flat tire in the rear and lose the axle key? You will be able to see the axle spin with the wheel on that side with it engaged, if so.
Peace,
Clarke