the auto hubs must be working other wise their would be no difference in the way it drives going from 4wd to 2wd, i have had a auto hub fail.
it sound more like transmision wind up than anything else, but could be somthing bent on the drive shaft at the front or somthing that is loose
This info may not be the case with the original thread but may help other members using their 4 wheel drive for the first time in anger.
Sometimes if the hubs are not engaged or disengaged properly, the hubs may start clicking, so go through the routine, engage 4 wheel drive, drive 3 metres forward, go back to 2 wheel drive, reverse back say 3 metres, repeat if there is still a noise.
Preferably do this on a loose surface or while one side of the vehicle is on grass/gravel just in case wind up has jammed the hubs some how. :nenau
Played with my Mav this morning in the snow, power turns are great, go into 2 wheel drive turn the wheel on half lock and power it round, it will turn on it's own length. On private land of course.:thumb2 With help from the limited slip diff.
To prove your 4 wheel drive is working do the same in 4 wheel drive, but you will need more space....:thumbs
You won't need to ask if your 4 wheel drive is working. Make sure the snow is slippy enough, you don't want to wind up the transmission...., too much.