wanders wilst in 4wd

hi all just wondering if anyone has had any problems with there nav driving all over the road when its in hi 4, I've never experienced anything like it you simply cant drive it in 4wd. and when you drive in 2wd it's fine. cheers

okay so i was told by arb the other day the reason why my air locker never works is because my rear diff was stuffed they sugested i replace crown wheel and pinion to fix the problem. nissan wanted 2000 bucks so that was a no go' so i bought a complete near new rear diff instead the guys at the wreckers said it would fit and was the right ratio, bow bow ' the ratio on my 2006 rx is 3.538 and the one they sold me was from a 2006 stx which is 3.692 thats why my steering is no good when it's in 4wd. so they are going to swap my front diff for theres problem solved, cheers