Depends upon the gear. If it's the RA worm or gear, you're in a bit of trouble because those are all unique to the telescope model. Other gears are oftentimes replacable as they generally are standard tooth sizes and getting a Boston Gear catalog will give you a part number for the gear - don't worry about the shaft size as you can always make a sleeve or drill out the center to fit your shaft. The problems with the RA worm and gear is that it is a certain size, usually both the teeth and the center hole, for the mount and also most worm and worm gears are mated for low tracking errors. If you have a stripped worm gear then you might as well find a new mount for the optics. The other thing is to place an ad in Astromart and other places that you need a broken telescope for the part. Good Luck! You'll need it!