I can speak from experience since I've rebuilt mine 5 times till I got tired of it and upgraded. It's garbage complete useless garbage. Everytime I would go offroading it would need a partial rebuild. Everytime in the snow or any cold weather it wouldn't shift properly. It always popped out of reverse and always would grind with every gear change. If I parked on a hill and put it in gear it wouldn't come out. If I stopped at a light and took it out of gear it wouldn't go back in.
All in all its just a really bad transmission, how its built how it comes apart and what was used inside it is all crap. Rebuilding a ba-10 fully with good parts cost around $600 and takes a ton of time. Rebuilding a ax-15 fully cost me $180 and took about 5 hours.