Four Wheel Drive Help

[Steelcity]

Hello all,

I have been a member of this site for about six months and always have found the information much helpful. My family and I are stationed at West Point, NY in the Army. As many of you know we are experiencing a major snow storm right now. I own a 2001 F 350 4X4 7.3. I was driving up a hill tonight and started to slide. I placed my 4X4 selector switch to 4 high and tried to proceed up the hill. Well that did not work. I tried my 4 low and that worked. Once I got home I had my wife work the switches. I found my manual hub locked in. I unlocked it and tried the switch it would not lock in. I tried the 4 low and it locked the hub right in. I am afraid that I blew the hub driving around with it locked in. I am thinking that the problem may be the vacuum pump or the hub itself. Does anyone have any ideas where I should start? Thanks ahead of time.

[Steelcity]

Well I got the truck to go into 4 wheel drive by switching it to manual on the hubs. After the snow melts I will clean the hubs out and hopefully it will correct the problem with it going into 4 wheel drive with the switch inside the truck.

[carolinaboy02powerstroke]

Switching to 4 high will only engage the front wheels if and only if they are spinning. It is meant to switch on the fly. I'm 99.9% sure that 4low will only engage in neutral with the truck stopped. Normally when someone has a problem with 4 high not working and 4 low works, it's a vacuum problem. Check all your hoses before replacing the pump. As a side note, normally when there is a vacuum leak, your heat will only blow out of the defrost. Hope this helps or points you in the right direction. We are here to help.