4X4 problems

I have a 2001 f-150 4x4 when I put it into 4x4 the light comes on and it gears it down but the front wheels don't pull. I've checked all the fuse's that I can find, is there some kind of a selinoid that is not engaing. I had the same problem with a chevy and that is what was wrong but I can't find the one for this truck. If anyone can help I would really appreciate it I'm tired of sticking this truck.

Here is a discussion of 4wd issues (http://www.ford-trucks.com/forums/showthread.php?t=391320&highlight=4x4+problems). Hope it helps. :smile: