1991 4wD tranny lockup

My 4x4 4WD Ranger has a manual tranny that locks up after going forward a few feet, sometimes more. it back up all day long but locks up going forward. some god awful noises (grinding, clunking, etc) come out of that gearbox. the 4wd is electrically operated. the ? is , can this tranny be rebuilt with a kit? i'm having great difficulty finding a replacement. are bronco II's compatible? engine is 2.9L V6.

on disassembly i found 2 meshing gears with broken teeth. can i buy these gears somewhere?