High Range lever disengaging

I have had 2 different 4wd vehicles that had high kms on them that did this & both of them required a gearbox overhaul to fix it.
Also my daughters car, again with high kms, was jumping out of 5th & this required a reco gearbox.
Not sure of the cause but the overhaul fixed them all. Sorry but it sounds like you might be in for an gearbox overhaul unless someone here can give you a specific guide to the actual cause inside the box

Cheers
Stu

This vehicle is automatic and has only done 150000

I have the same car but manual 4wd. I'm no mechanic, but it appears that an
electrical action is causing a mechanical disegagement. I would be exploring the
electric side first before worrying about the box. .......oldbaz.

I have a Mitsi doing a similar thing at the moment. Most modern 4X4's use vacuum to engage 4wd and they use switches that tell it to go in and out, mine has to switches inside the box, just under a cover on the top. We put mine on a hoist a couple of nights ago and if we put power straight to the wire, the solenoids go straight in, so I would have a look at electronics first off. My vehicle has done 115,000k's but mitsi's have 10year or 150k's on drive train, so we will see how i go next week when they take it in. :-)

Ok guys thanks for your help. Yesterday I went to a auto electrician and he had not come across this problem before so he told me to go the local holden dealer.
Well I may as well sat & had a talk to my dog about it. He did not have a clue & the guy in the office said he was an expert on Jackaroos. I have worked out the transfer box is OK if do not try to switch on the 4wd button on the dash. It is only when you activate the switch is when I have this problem . So members BLAZE & OLDBAZ I think are right so I am going to find out what bit is causing the problem. Thanks once again