What kind of trans is it? Gear driven or hydrostatic? Lever on the fender, or between your legs. How many speeds, big belt driven pulley on top, on the side, etc.
Take the bolt out of the bottom of the case. Just a simply threaded pipe with a square tip. See if any fluid comes out. If it does, note the color, and see how many gear shavings come out. It may be savable.