a common fault on all lt230 tranny box's is that inside the selector housing, where the actuator arm join's onto the selector shaft, there is a little grub screw, and it has a nast habbit of working itself loose and thus allowing the arm to spin on the shaft, if no joy with the linkage take the cover off on the top of the transfer box where the linkage goes to and have a looky,
post a reply if no joy with linkage and i will post some pics of the housing which you need take off