Sounds like the dog clutch in the front axle assembly is slipping. If it's the air-actuated style I would speculate that it may be caused by an air leak or weak pump.

When you say it goes from 4H to 2H by itself, do you mean the transfer case lever actually moves?

 

Yeah the transfer lever physically moves from 4H to 2H and there is obviously a clunk when it does this.

 

Forgot to say that I have since tried 4wd on the road and 4L works fine, I assume the problem only occurs whilst under load (soft sand etc). When put in 4H on the road it goes fine for a while but eventually kicks back into 2H of its own accord ie the transfer case lever moves by itself back into 2wd. Everyone has told me transfer case but no specifics. Also heard at is a chain driven transfer case and the chain could be lose and slipping? Is this a likely cause?

Please help because I am trying to get an idea of the severity of the problem before I take it to the workshop.

Cheers!

 

if your transfer lever quickly release to 2H after shifting t0 4H, the only way to solve your problem is to open your transfer gear and put washer on one of shifting fork for high speed gear(4H gear). how to locate where you have to put washer??? after you opening transfer gear there is two shifting shaft inside it, look for the shaft that have a return spring (it is the one we need). the position of each parts are these_e-ring-fork-spring-washer-e-ring. now, additional washer must put in between the e-ring and fork.
washer is the same as in the other side (part # is 09181-14167)
hoped i help you about your problem....
good luck!

 

Transfer Problems

I have the same problem with mine and this is the conclusion that I have come to...
Have a read through this thread that I started.

auszookers › Forums › Tech › tech chat › GV High Range Problems