I own a 01' f-150 4x4 offroad package xlt, with turn of the ****, shift on the fly.

My question is that it doesnt wont to engage in to either 4h or 4L. the dash light does light up but it doesnt do any thing. Sometimes it will click into 4wd, if it does as soon as i put a little power to the wheels it kicks back out. Does any one know or have this problem before?
My guess is something with the hubs.
I checked the forum but didnt see anything about my topic except for a few vacuum lines.
Thanks for the help you guys can give me. I am only a college kid that puts all his money in his truck.

 

I haven't had any trouble with my '02, but if I had to venture a guess, I would suspect the vacuum actuator on the front differential or the vacuum lines that feed it. When rpm goes up, vacuum goes down. If you are loosing vacuum somewhere, there won't be as much available "off-idle"

The secret to keeping a 4WD system in order is to test it out when you DON'T need it---or you could find yourself in a jam.

"College kid that puts all his money in his truck" ---boy do I know that feeling!!!!!! Enjoy it now, once you "grow up", you'll have much more important albeit less fun things to sink your money into.

Sidewinder

 

This may help you. I had to drive from ohio to upper michigan in saturdays snow storm. I had four wheel drive on the whole time and was working fine till I stopped for fuel and food. I turned my four wheel off as I pulled in to the restaurant to keep from knucking around the snow cleared parking lot. Half hour later, took off again heading north and engaged four wheel drive. The truck felt different, back end kept breaking loose. Stopped at a rest stop and had the wife watch my wheels as I tried to spin them in the snow. After five minutes explaining to the old lady the difference between spinning and rolling I determined the front was not engaged. crawled under truck and had her shift in and out of 2H and 4H. Drive shaft was locking in but axle was not. Traced vacuum lines up to passenger side control solenoids which were encased in ice from the snow that melted then refroze on top of them. Drove rest of the way in two wheel. It was cold the next 2 nights -17F. When it warmed up to 26F and we drove home my engine compartment thawed out and my four worked again although I didn't need it as the roads were clear.