4X4 not locking in

[04_powerstroke_71]

I bought an 04 f-350 about a month ago and today at the beach I bogged down and I was told by a someone that watched me get stuck that my front tires werent digging. I was in 4 low and my lights for 4x4 and low range were on. What could be wrong?

[Colotow]

either transfer, front axle or hubs
put it in 4 low, (engine off, set park brake, block tires) jack up front end, try to spin the tire. watch to see if the ujoint spins in the knuckle. then check other side. back down on ground, try to turn the front drive shaft by hand.
this should help narrow it down

[greasltn]

Most likely the hubs didn't lock in. Usually caused by a vacuum leak at the hubs. If you manually lock them in it should work.

[Bax]

I don't want to high jack but my truck 2000 7.3 crew is having the same problem. Today on a jobsite I needed the 4 WD. I got the light and even low range but no drive to the front end. Another odd thing was when I turned the 4wd selector knob my A/C stopped blowing out the vents and seemed to be coming out the defrost? WTF? I never got the front to pull but when I turned the 4x4 off my A/C came back. Anyone know what's up?

Thanks for any help.

[Colotow]

sounds like a leak in the lines to the hubs, the vacuum pump operates both, so when you tried to engage 4x4, all the vacuum leaked off.

[greasltn]

I agree, it is a vacuum leak. It could be the lines going to the hubs, or in the hubs themselves.

[Bax]

Thanks guys I will look into it.

[brock21]

i actually kinda have the same problem. i took it upon myself today to try and figure it out. so i took the passenger wheel and hub apart because i had narrowed it down before. everything was good. (first problem) i took the warn hub apart and notice that it was not engaging because the axle moves around a lot in the hub. (second problem) when i was putting the cover back on the hub i noticed while i was srewing it in it would bring the big gear in there out to fare for it to engage. so i took it back apart moved the axle around in the knuckle so it would engage and it did lock up. so i thought about just running it in locked for the time being but i go to put it back together and me screwing it in pulls it out to fare to engage. its a 2002 f250. any help would be much appreciated.

[7.3Leader]

Ok, I just got back from the Ford Dealer. I was having the same problem with the hubs not locking, on my 2001 Ford F250. Although the A/C would continue to blow through the vents (not swtich to defrost). Turns out both hubs have a slight leak and are not locking. The dealer has quoted me $500 to remove hubs, clean, replace seals and re-install. Is this something reasonable or should I do it myself? Also they were having problems finding a Ford part # for just the seals. Can anyone help with that?

[Bax]

On mine I had 2 bad vacuum lines. I fixed it for under 5 bucks. If you don't need the other work it's not a deal. Check the lines from the hubs to the pump.