4X not engaging

[Baysmith]

I have this same issue with the 4wd on my 05 F250. They will engage manually but not automatic. However, When I turn the switch to 4wd the A/C switches from the dash vents to defrost. Any clues on this? Vacuum Hose loose? Thanks.

 

[Clyde99]

Baysmith, that sounds like a vac. leak somewhere.

 

[DaveBen]

Check the vacuum lines going to the wheel assembly. This seems to be where they leak or come loose.

Dave

 

[wrightracing.net]

4WD Problem

I just had the same problem but I found that I two problems. First was the vacuum lines were cracked and the main problem was the plug that goes to the transfer case was loose. The plug is super hard to click into place but once I got it I was good to go. Works great now.

 

[mrziggy]

I had an issue like that just last week after seveal months of not using it. Once I used the 4x4 by manualy locking the hubs several times and selecting it in the cab, it seemed to clear up and is working fine now. Perhaps it is just stickin? I spose you already covered that though.

 

[Metalhead]

I'm having this issue with my truck too. After I had run the truck in 4hi, I noticed that after I went back to 2wd, I was hearing some clunking coming from the hubs immediately after, louder than what I'd want to hear. I backed up slowly, thinking it was just torque bind, and after that I had no noise. This was about 2 weeks ago, and now I notice that I have the same issue as the first post here: When I engage 4 wheel, I have to manually lock the hubs, the auto feature doesn't lock the hubs anymore. What would've been causing this loud clunking I heard two weeks ago?

 

[Super 05]

Can the axle seals be changed simply by pulling the axle out through the hole where the hub mounts to or do you have to remove the knuckle and the whole 9 yards?

 

[andym1996]

Guys - had the same exact problem as all of you
- defrost when trying to engage the 4x4
- no front locking hubs (when in auto)

Diagnosed it as the solenoid by removing the vacuum line, and putting my lips around the tubes going into the solenoid, blew and hard as i could... drove it a block, the 4x was engaged... installed the solenoid - good as new.

I'd bet on it... let us know.