If you have not done so already; remove the final drive drain plug and let it empty into a clean plastic container. Once all the hypoid is drained out -- use a magnet and stir it around in the plastic container. If you find fragments on the magnet that will indicate that you chipped a gear. If you did, you can replace the whole rear end unit buy buying a used one. If the hypoid come out "clean" you will need to determine what the problem is by doing some trouble-shooting. Trouble-shooting the rear-end is a whole days work -- so to speak! Back brakes off and checked for binding. Drive unit pulled and checked for function off-bike. U-joint inspected for failure and either rebuilt or replaced with new. Beyond that ... you get into the very serious issue of middle-gear inspection. But, since you said the engine started and ran but the ass-end didnĀ“t move -- your problem is probably going to be somewhere between the rubber boot covering the u-joint--back! + + + Good luck with it. RickCoMatic