Hi,is there a knack to changing into low box?,i have an 1986 vogue auto,from the normal driving position(bottom right,high range no diff lock)i can move the transfer box lever to the left to engage diff lock and the light comes on the dash to indicate this is working,however from here i cant move the lever forwards to engage low box,could it be seized,not had car long and previous owner(12 years)didnt use off road,please help,thanks,chris.