These trannys are dirt simple to work on. Theres about 10 moving parts. As for the first and reverse gear, it will be mostly chewed up on the 1st side, (since it sees first more often then reverse) and the gear can be turned around so that the chewed parts are on the reverse side. They come up often enough on ebay and I think I paid $10-20 bucks for mine.
Do you have a copy of the three speed rebuild manual? I can shoot you it in a few emails if youd like.
Jeff
