Did you post this in the 1997 - 2003 F150 forum? I would think you would get a quicker response there.
If I remember correctly your system have a switch on the dash which can cause problems with engaging/disengaging same thing with the front disconnect unit. How those work and how you troubleshoot them I am not aware of. Hopefully someone else will come along and can shed more light on your issue than I can. Good luck to you!!
thanks for the info,mine has the shifter on floor im going to crawl under to check out
Those can bind or the linkage can come out of adjustment preventing you from getting it out of 4x4. Hopefully it is the linkage on the outside of the transfer case giving you issues instead of the linkage inside.
Let us know what you find out and good luck with it!!