Hey this is my first post and have been reading on this issue here, but my problem is giving me a hard time to figure out.

My truck is a V10 and I just purchased it a couple months ago. It has the auto and lock hub positions. When I turn the **** to 4x4 it says 4x4 is locked in, but when I take it out in the field it's not engaged. I can also put it in neutral and engage the 4x4 low , and on the dash it will say 4x4 low, but its not engaged either.

I can go out and turn the hubs to the lock position, then engage the 4x4 drive the vehicle a few feet and it engages 50% of the time. Sometimes I have to try it a few times. It will spin the right front.

Then I can turn the **** to 2WD and it will disengage the 4x4, but it might take a couple days of driving for the light to go off. It still Says 4x4 on the dash, but not engaged. This doesn't matter is I turn the hubs to auto or lock. Light will stay on.

So it's like sometimes it works and sometimes it doesn't. Here is what I have tried and confirmed..

1. The defrost gets ultra hot and blows air, so don't think a vacuum leak.
2. I can turn the **** while the engine is off and hear the solenoid try to engage ( kinda sounds like a fuel pump first come on) it sounds a light click. Also, if I turn it back and forth with the engine off I can only hear it once. In other words I have to turn the key back off and in then turn the **** to hear it.

3. I figured fuses and relays are ok because it works sometimes. Also, the dash light works so figued no fuses are blown.

At this point what could I check? Could it be something weak or going? What about the hubs? Figured they aren't stripped because it's the light that doesn't seem to be working, but then again the truck will not engage 4x4 at all when hubs are in the auto position. They have to be in locked only to even give it a chance to work.

Why is that?

Thanks for any help. New here and very excited to own my truck.

 

Sounds like another truck that has not had the system exercised regularly.
The vacuum leak test for the auto hub is here many times over.
Quickly tho , with the truck running, put the heat to the floor and verify.

Turn the transfer case selector to 4 hi, and put your hand on the defrost duct, to see if the heat goes to the defrost duct, that is the default .

It may take a few minutes, it may not even happen.


On to the manual 4 positions,
My opinion ion is the motor is stiff, has not been used much if any.
Remove it, set up a bench test jig, and spray that mechanism with a good penetrating like PB Blaster, while applying 12 volts to the motor in both directions.
The motor should click into position quickly, not like you said a fuel pump priming .

For what it is worth, I do t even use the auto position, lock them In and leave them.

 

Thank you for the response. I will try this out tomorrow. One question where is the 4x4 motor located? Is it the solenoid on the bottom of the transfer case?

Thanks again for the help.

 

Update on my ESOF 4x4 issue. I did have a weak PV solenoid. Replaced it today and the problem has gotten better, but not completely fixed.

I just purchased this used truck recently, so not sure if they used the 4x4 a lot or not.

The vacuum leak seems to be fine, but when I turn the **** over to 4h it engages within about 3 seconds. Sometimes the truck has to move forward or backward, or I have to turn it off and on a couple or more times to engage.

It is currently locked in 4H. I drove it down the road, turned it to 2W and it didnt disengage. Also, the light on the dash still says 4x4.

Did it a couple more times, then stopped and backed it up, well then it disengaged and the dash light went off. Drove it and then engaged again, the light came on in about 3 seconds, then the 4x4 engaged again.

I turned it back to 2W and the dash says 4x4 and its engaged. I can feel it in the front end when driving. Now when i turn it back to 2W light stays on to 4x4, and its still locked in. I can stop and go back and forth and it will change.

I am thinking now it could be the ESOF GEM module, or the transfer case motor or solenoid? What are anyone's thoughts here?

All fuses are good, I have switched relays under the hood as well. Although with it working sometimes, figured these were good.

Where should I check at this point? Also why should I just leave the hubs in LOCK all the time vs AUTO all the time? What does it do? will it hurt anything?

Thanks so much for the help. I am a new Ford Truck owner so trying to learn how to work on these.

Thanks,

 

Ok the light on the dash is a key bit of information. If the light still says 4x4 when you have switched it from 4H to 2H, it means the transfer case motor never completed the shift.

The sensor for gear position is in the transfer case motor. If backing up and going forward gets it to finally change position, it is not the 4x4 module. Could be a weak transfer case motor or sticking components inside the transfer case.

There isnt much to take a transfer case apart, but you should start with swapping in a transfer case shift motor.

 

This helps a lot. I will start looking at the transfer shift motor then.

Thanks so much for the reply.