I really don't mean to try and thread steal this, i just didn't want to start a whole new thread with a similiar but different problem.
I also have an 04 FX4 and was wondering about the 4wd. I know in my last truck (which unfortunately was a chevy, but got smarter and bought a ford) it had an auto 4wd. When i switch my 4x4 in, it almost seems like it goes in and out sometimes. The reason i was asking, is it something like the auto 4wd my chevy had where if it felt it slipping it would kick in and out, or should it be in all the time?