I had to make a few trips up and down the snow covered driveway. I moved the dash switch to 4wd high for each trip and then back to 2wd when I was turning around at each end. On my final trip back, I got stuck while turning around in 2wd. I tried switching to 4wd high and low but could not get either to engage with rocking back and forth. The dash light did not come on and only the rear right wheel was spinning. Shifting to park or neutral and turning the switch to 4wd did not change the results. When I finally got myself unstuck, the 4wd still wouldn't engage when driving in a straight line.

What could have broke or stopped working? Bad vacuum line? Bad fuse? Could I have still initiated 4wd by manually locking the hubs? If so, is the process with the dash switch still the same even when manually locking the hubs?

 

I'm new to this ford shift on the fly system without manually locking the hubs.

They way I understand it is. With the hubs on auto setting. Setting the switch in the cab to 4 WD supplies vacuum to the knuckles on both front wheels which goes to the hubs to lock them in.
Many problems seem to come from lack of vaccum.

Locking the hubs manually, then switching to 4wd should work if your electronics are working.

Use the search an enter 4wd not working. You will find a lot of info.

If I'm wrong on any of this info. Someone please correct me.
I'm used to manual shifters and hubs. Not this auto-magic new stuff.

Good luck

 

The dash light is only connected to the transfer case engagement.

So I'd look at that end of the system,

There is no dash indicator for the hub system. Maybe they are working maybe not....your computer doesn't know.

 

FYI The auto hubs are junk. Replace them with a good set of Warn or MileMarker manual hubs. I know thats not just my opinion either.

 

Think of the auto hubs like a retractable ink pen. You can click it out or in. It takes longer to click one way than the other...The hubs are similar and the vacuum pulses supplied are long or short depending on engaging or disengaging. It's not a constant vacuum or it would slowly fill your engine with muck as soon as it leaks, which it will. I agree with replacing them with manual hubs if you want to increase the reliability of the system engaging and disengaging when you want it to. None of this is your primary problem though, the others covered that. Your transfer case wasn't engaging.

 

x3 for the transfer case is not engaging.

Lots of info has been posted in this forum and the diesel forums on this topic. All the info you could need is at your fingertips.

 

The last time this happened to me I almost drowned my 6.0 Excursion....

The culprit was the two relays below the hood near the underwood fuse box. I replaced them and my transfer case started engaging again. Before the light would come on the dash, but that's it...

If for some strange reason it still won't work, check the solenoid on the passenger side fender., it has a single plug going to it along with vacuum lines. Try this provided that your vacuum lines going to the hubs themselves aren't dry rotted.

 

It could possibly be an electric issue. Bad ground maybe? I've used manual locking hubs all my life and just recently started learning about the auto stuff, so don't hold it against me as its merely a suggestion.

 

Can someone please post a link in this thread for the braided hoses that replace the vacuum hoses.

And also a link for aftermarket hubs that are better than the stock ones?

Im assuming Summit will carry them.


Thanks.

 

Since you can manually lock them, I wouldn't trash them unless you just want to do so. I agree those are good replacement brands

I have lamented over the ESOF through 2 Excursions now. I was a purist and wanted the auto lock hubs to work just like they are supposed to. As Pirate pointed out, there is no indicator for the hubs. Currently, my right hub will autolock but the left will not....so I just manually lock them. One locked hub is a recipe for disaster. You hit ice like that you better have good insurance...trust me I know. Now I just manually lock them so that I know they are locked--I don't like guessing FWIW

 

Problem is, you can manually lock them, sure, but you can not ensure they manually unlock. One may stay locked on you.

 

Sure you can, reach in and turn the axle at the ujoint by hand. If it turns the hub is unlocked, if it doesn't turn the hub is locked. ( it takes a firm twist to get the axle to turn )

 

Well learned something new. You know you just sent my paranoia through the roof. How about locking them until they croak?

 

I had an accident because my ESOF did not engage my hubs. Luckily nobody was hurt. I only will trust my hubs locking/unlocking manually.

 

Yeah I just don't wanna lay under the truck on each side every time I use 4x4 only to have to fiddle with the ESOF hubs. One of mine was so bad I had to remove it to unlock that side. It worked for a few months after doing the cleaning procedure but went right back to its old sticking ways. So while they are manual, they don't work as well unlocking as true manual only hubs.