This is long but I want to give the entire scenerio.

two months ago i briefly used 4wd to get out of a wet/muddy spot and everything seemed fine. I then parked the truck until later that evening. Jumped in the truck to take my girls to soccer practice and halfway there I noticed the engine reving high but yet I was slowing down. The best way I can describe it is if I was stuck in 4wd low or in first gear. I made it to the fields and pulled into a parking spot and put the truck in park. While in park the engine revs up and idles at 2500rpms. I can put the truck in drive and reverse and it seems to go into gear fine. I make it home after practice but it was still having the same problem. The next morning everything is back to normal. I have been driving the truck since with no issues until today. Last saturday I shifted the truck into 4wd low to move a trailer around the yard. Parked the truck until today Friday. I drove 5 miles to home depot to pickup some plywood with no problem. While driving halfway home after stopping at a stop sign the truck does the exact same thing again. Engine idles at 2500rpms and does not shift correctly.

ANy ideas will be greatly appreciated.

Thanks

 

Welcome to the site..

What year 250 and what engine?

 

Its a 2002 F250 crew cab xlt gas engine 5.4

thanks

 

I could be wrong, so input from other would be helpful. But i believe that model year had vacuum hoses going to the hubs that engage the 4x4. I would check all the hoses to and from the hubs and the vacuum resivoir if it has one, and make sure noting is damaged or leaking.