mines got 130k on the clock and an entirely different gear box but i sometimes have to go to first gear and push the transfer box stick to where i want it while lifting the clutch to get it in.
same for me,
AFAIK the transfer box gears are straight cut sides, so if they are out of line, they wont engage, doing wither of the above moves things around, and they usually go in the 2nd time around.