I have a 1995 arctic cat 580 ext snow mobile with aftermarket reverse, anyone know how to fix or have manual?

1995 arctic cat ext 580 snow machine with aftermarket reverse, the reverse is causing it to go out of gear when you are going forward, but when you press on the brake it goes back into gear. what can i do? anyone have a manual i can buy or know how to fix?|||yep|||no sorry,,ask the dealer|||You should find a book on the internet, or go where you bought it and ask for info on how to get a book. Good luck %26amp; good findings.