Transfer case problem

[chickstr]

I have a 1995 explorer xlt. When I turn the dial while driving to 4wd high nothing happens, for a minute, then the dash lights start to flash.. When I turn to 4wd high when I am at a standstill the lights come on for 4wd but there is a massive clucking/rubbing noise, after about 2 min the lights begin to flash. It worked once for an entire day last week perfictly then the very next day, back to the same problem... HELP!!!!!!