Went to engage 4x4 low in snow and mud. Front axels did not engage, just spun the rears. Had to lock them manually, then it worked. What to look for?

 

My 04 did the same thing. I replaced the solenoid for the vacuum pump, located inside passenger fender. It fixed it right away. I ordered the Dorman solenoid on ebay for $28.85 and it took minutes to swap out.

 

Have you checked to see if your hubs are actually unlocking with that Dorman solenoid? I tried 3 new Dormans and my hubs would lock fine, but not unlock. I replaced it with am oem solenoid and they unlock now.


Back to the op's question. First thing is to check for vacuum leaks. Here is a link to good description of the system; https://www.ford-trucks.com/forums/1...l#post15405441

If you don't have a mighty vac to check vacuum, Some Autozone stores have them in their loaner tool program that you can use. You can verify if your vacuum hub lock solenoid is working correctly with the mighty vac and check the rest of the system for leaks. If you get a mighty vac and would like some directions on how to check your esof with it, let me know.

 

Or just manually lock them from now on. Just as easy. I replaced the auto hubs in my 2006 F350 with manual Warn hubs a few years ago. I just leave them locked all winter.

 

Everything worked fine. Maybe I got lucky? I'll check again when I get home from sea though. Thanks for the heads up up!

 

Will be checking on those.

 

Hello All,
My front axles would not lock in today while trying to pull out a shrub in my back yard. Unfortunately I was on a slope and my truck kept sliding toward a tree. After trying for some time to get traction to the back tires, I tried manually locking the front hubs. The old girl drove out of harms way like a 4x4 should.

So I guess the auto hubs were not engaging. Now to check for vacuum issues and go from there. Is there harm in leaving the fronts manually locked all the time? Thanks. B.

 

What's the proper way to diagnose the solenoid? My new to me 05 also does not engage the 4x4 without the hubs locked, and I've noticed when I turn the key on first thing in the morning the vacuum pump runs for quite a while. I know vacuum leaks aren't common in the ESOF system on these but maybe I should start there?

 

 

No, but when I first turn the key on after being parked overnight the vac pump runs for a few minutes. After shutting it off I can hear what appears to be vacuum being lost from somewhere near the heater core area but the pump only runs after it's sat overnight. Climate control does not default to defrost when placed in 4x4 (watched a YouTube video that showed this was one way to isolate the problem). I have a Mityvac but it doesn't seem to be doing it's job anymore so I wasn't able to test vacuum at the hubs or the solenoid.