mmm don't know about you box . But on a 85 range rover box (in layman terms) there is a lug that stops the bar for the diff locking going back. This wears and somtimes and will not hold it and then engage diff lock.
But also could just be crap under the gear lever that is causing it not to go all the way home. Will feel it from the gear nob inside the car that it is going in and out but not doing anything underneth. So have a look and make sure the rods are clear of crap and not damaged
if you have any burring on the gear spurs that lock the Center diff they will bind in lock...
fortuanetly its an easy fix.. but the repurcussions are not friendly...
When youve moved it would pay you to check your Diffs and axles for damage, if they look at all suss then go the cv joints as well..
If its a damaged bush they can (in conjuction with your suspension) in the right circumstances make a repeating hammering type noise...
But then so can 2 loose wheel nuts if they are next door to each other.
this is exactly what i had fixed on my 86 rangie today what Reads90 just described the lug was not holding it the unlocked position but the my diff lock light was not coming on but i knew it was engaged because i could feel the wind up i caught it early so know damage done and was not expensive to fix.
All the best Mark:) :)
Anyone got some RAVE info or the like for this lug ? Prices / where to get the part .. sounds like what I am having with.
drain the oil in the transfer case and see how much metal is stuck to magnet on the back of the drain plug, will give you an indication as to if there is any damage internally