1998 Auto Disco1, Transfer box does not do anything when I change from H to N or L, just drives as normal. I am assuming there is a broken link, any known problems or where to start. Just got the vehicle about 2 weeks ago a bit green on how to access all bits.

remove consol and drill out rivets of rubber gaiter linkage goes from lever housing rearwards can break or come undone ,also if appears okay selector housing on t.box 6 x bolt has lever on inside of housing that is secured by grub screw that can come loose