dime06

I have land cruiser VXR and prado and both stand still at steep places when gear is at N - ( i have a traffic signal at a steep hill ) but my LX570 doesn't stand and after few minutes i hear some cranking sound and then it slips backward and i have to apply brakes .. dealer say this is normal but i dont except as why my LC and prado remains still and lx570 doesn't or is there any "setting' required , appreciate your comments on this...