So my ESOTF only works sometimes. I can switch it in and hear it click and it will be in 4wd then just unlock itself. When I'm going off road I have to lock out my hubs or ill end up stuck. I'm thinking it has to be an electrical issue since its intermittent.

 

Its your hubs not holding vacuum. Very common problem. Check the vacuum linesgoing to each hub. Maybe youve got a holein one of them. Chances are the hub seals are leaking.

 

I am having the same problem too

I suspect vac leak Like Steelhead says


going to troubleshoot Over the holidays I will post what I find

 

I thought if there was a vacuum leak it would do something with your heat. Something about making it blow out of your defroster when you turn it on. Maybe I'm crazy.

 

Oh no your right

a Big leak will make heater default to defrost

High Vac Locks Hub in

Low Vac Unlocks the Hubs


And I also think a Bad Vac relay would cause intemittened hubs Lock and unlock

 

That's what I was thinking like maybe it was acting like an electrical short. Like it locks but when it gets bumped a certain way I lose the vacuum and it unlocks. But wouldn't it default to defrost when I lose the vacuum though? Mine never has done that.

 

Could be Electrical Problem shure or Vac Silinoid and Honestly probably more Common for this type of condition Now I think about it





We Might have Bad Vac Control silinoid


The More I look at the 4X4 Vac for Hublock diagram the More I thinking its the PVH Silinoid thats gone bad

Or Bad wiring/Fuse to the Vac Silinoid

 

According to info I have The Vac is Only applied for

51seconds to Lock Hub (45 seconds High Vac with a 6 second Vent cycle at the end)
&
15 seconds to Unlock Hub (15 seconds of Low Vac)

so there isnt Constant Vac Pressure as far as I can tell



So I am thinking that the PHV Silinoid can develope a Leak (An Internal Leak) and create the Low Vac Condition what would Cause the Hub to UNLOCK

I am thinking that a Bad Hub would also create Intermittened issues in addition to the other therory

 

I was attempting to use my 4wd today as I was driving in some muddy areas and got stuck. My back tires just spun in the mud. I switched it into 4wlow on the dash but did not notice the front tires spinning. I then got out and manually locked the hubs. Again Did not notice the front tires spinning. Had to be pulled out by another vehicle. Any ideas or suggestions??

 

Well to Acheive a 4 Low engaugment very specific conditions MUST be Met



vehicle speed must be below 8 km/h (5 mph).



Mis 1 step and 4Lo in No GO


----------------------------------------------------------------------------------




Did you try 4x4 High???Lots fewer conditions to engauge 4HI

I bet it would have worked in 4HI

 

I tried both and did not notice any difference. This truck is new to me. I did stop, kept brake applied, shifted into neutral then turned switch on dash for 4wd low.

At least the vehicle that pulled me out was another Ford.

 

That SUCKS Easy just went out the window



Ok then I am thinking a 4X4 Relay or Slimer chance a GEM Module A Fuse or Wire Problem or Bad Shift Moter

The 4X4 Relays are by the Master Brake Cylinder IIRC

Lock the Hubs and Make Shure you cant spin the Axel right at Ujoints at Steering Knucle Basicaly is it locked together




The Hubs do need alittle spin to get right position and Lock but once you went Manual Lock they should Lock

The Drivelines Must SYNC But I am thinking they Did just by rear tires spinning

 

Thanks Blade. I tried putting it into 4 low again tonight and it worked fine. I think because I was not moving, I could not get it to go into low. I was also able to put it into high as well. Maybe I just had a brain fart and was not doing it right the first time.

 

Sorry for the
We had some snow the other week and going into 4H
I had the heat move from the vents to the defroster for about 30 sec and
then back to the vents and I did check and the front wheels were pulling.
It was just odd that it did that. What do you think do I have a wheel seal going?
I really don't want to have to do that job, But if I do I guess I may as well do
the ball joints at the same time. I know that they are at about the replacement
point anyway getting a little bit loose. I'll top it all off with a replacement of the
steering gear box with a Red Head Steering Gears - Home
One thing do the hub units have seals in them also?

Sean