I have a 2002 F-350 Diesel 4x4 with an auto trans.and 100,000 miles. It is an electronic 4x4 switch on the dash. It has recently started to act up. I will shift into 4 high, and it will lock in, and drive for a minute or 2 and then disengage. The light still shows it being in 4x4 but you can spin the tires. When you switch to 2wd and back to 4x4 it will do the same thing. No hesitation etc to go in, but just comes back out. It even went back to 2wd and then back to 4x4 once or twice by itself. Would this be the hubs? I have never service the hubs or 4x4 at all. Any ideas?

 

My manual hubs went out in my jeep and it was just gone, It didnt just fall out randomly. My friends jeep had the main gear in the tcase wear out. His four wheel drive would just engage and disengage, it more happened when he was coasting rather than under power. i know this doesnt help out to much, but thought i woud give some insight.