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Discussion Starter #41
I try to get in the habit of checking my hubs, however the one time I forget is the one time they end up being locked.

I'll get a new solenoid because I know I'm getting vacuum but it won't automatically go into 4x4 anymore.
 

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Man, this is quite confusing. The actual hub has two choices. Auto or Lock.

Auto will relate to trucks equipped with the ESOF system (which you have). If there is a vacuum seal leak, the hubs will not (or should not) lock. The only way I can see them locking manually is someone turning them while your sleeping, or there is some serious issues inside the hub. It is known that water used to get into the vacuum lines on some of the older systems and would eventually mess up the hubs completely because water would actually leak down through the vacuum lines and pool inside the hubs. But from the videos I've watched, that was when the solenoid and vacuum canister was mounted on the firewall or maybe on F150's.

Now, just so were clear, the system is very picky when engaging and disengaging, depending on if you are trying to use 4WH or 4WL. Switching to 4WL should be done in a series of steps and at speeds under 5mph. 4WH can be done while driving as long as you are under 55mph. Both switching into and out of 4WD takes at least 30 seconds. You have to give the system time to create the vacuum or release the vacuum. Even when doing this, sometimes getting in and out of 4WL can be tricky. For the selector switch in the cab, you should only move the selector one at selection at a time and wait for the system to do it's thing. So you would go from 2WD to 4WH first, then wait for dash light to show "4WD". Then you can go to 4WL (as long as other parameters are met) the 4WD "LOW" light should come on. Same is true when going back to 2WD. First, go from 4WL to 4WH. Wait for "LOW" light to go away. Then switch to 2WD, and wait for light "4WD" light to go away. This also may require rolling forward for it to disengage. This said, hopefully that will help clear up any confusion on how the ESOF system works. A simple test on the vacuum lines using a vacuum gauge will tell you whats happening and if the pump is doing what it's supposed to. Remove one line at a time at the hub. Hook up the gauge. Grab a friend (and a beer). Have one person in the truck moving the selector switch as explained earlier, while one watches the gauge. Once you do this, let us know what happens when switching between 4WH and 2WD. For test reasons, no need to switch to 4WL. The main purpose is to see if the vacuum is building and releasing like it should.
 

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Discussion Starter #43
Someone had mentioned something about detents and the hub locking into place. I thought it was locking into place, however after sitting out there and locking / unlocking it when I felt it "locking" into auto, it was just overcoming friction, the more I spin it the freer it gets but the only true lock is when it is in 4x4. When it's in auto there is no difference from half way around to all the way to auto, it's all one smooth motion with no detents.

I did try to just switch it to 4x4 and go, so I'll try to wait a little bit and see what happens. I don't have a vacuum gauge or anyone to help me out and I can't buy beer yet, so could I switch it to 4x4, pull the vacuum line off at the hub and see if it's getting vacuum with my finger?
 

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Just leave the hubs locked and use the switch on the dash to engage 4x4 when you need it.
Why do that? You'll be dragging the front axle all the time. The only way I'd do that is if I was in a 4wd situation and my ESOF was leaking (like mine does)

When I did the test today my 4wd light does come on, however the front axle does not lock unless I go out and lock the hubs. It is a switch on the dash, not the stick on the floor. 4x4 does work if I flip the switch and go out and lock the hubs.

I would leave everything locked, however that puts more drag on the driving components using ever so slightly more fuel, not to mention I'm sure it wears out parts. I also just prefer everything working properly. If it was a beat up old work truck I would have no problem with a little duct tape here and zip ties there but this is a nice daily driver.
Vacuum problem, but still doesn't explain the turning toward lock. Borrow a game camera and park your truck where it'll catch whoever is doing it. There is no way they are turning themselves.
 
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I did try to just switch it to 4x4 and go, so I'll try to wait a little bit and see what happens. I don't have a vacuum gauge or anyone to help me out and I can't buy beer yet, so could I switch it to 4x4, pull the vacuum line off at the hub and see if it's getting vacuum with my finger?
Did the 4WD light come one after you did this? I don't know how well the finger method is going to work. The vacuum pressure is not very high and the amount of pressure is sort of important to know if it's working correctly. A cheap gauge (under $10) would be wise. Also, you really need to watch the gauge while someone switches it for you from 2WD to 4WH and then back to 2WD again. Repeat both steps for both sides. And like I mentioned, allow time for the system to build pressure or release pressure (approx 30 seconds) every time you switch between 2WD and 4WH.
 

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Discussion Starter #46
Why do that? You'll be dragging the front axle all the time. The only way I'd do that is if I was in a 4wd situation and my ESOF was leaking (like mine does)



Vacuum problem, but still doesn't explain the turning toward lock. Borrow a game camera and park your truck where it'll catch whoever is doing it. There is no way they are turning themselves.
Is there supposed to be a detent to lock it in the auto position? If there is and since mine doesn't have it then maybe when I'm driving they just work themselves to the lock position? I do have the camera situation figured out, my dash cam runs 24/7 and starts recording as soon as it sees movement so next time I see my hubs are locked I'll pull the dash cam and see. My truck is always backed in right next to the RV so I would either see them on dash cam going around the front of the truck or a clean mark on the bed where they are sliding up against my truck.

Did the 4WD light come one after you did this? I don't know how well the finger method is going to work. The vacuum pressure is not very high and the amount of pressure is sort of important to know if it's working correctly. A cheap gauge (under $10) would be wise. Also, you really need to watch the gauge while someone switches it for you from 2WD to 4WH and then back to 2WD again. Repeat both steps for both sides. And like I mentioned, allow time for the system to build pressure or release pressure (approx 30 seconds) every time you switch between 2WD and 4WH.
4wd light came on within a couple seconds, then I put it in neutral to put it in 4 low and the low light came on as well. I'm just getting ready to head out and retry the 4x4 and vacuum lines so I'll report back in a little bit.
 

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Discussion Starter #47
Ok so if I wait a little bit when the knob is in 4x4 it does lock up in both 4 high and 4 low. Again confirmed all vacuum lines are staying pressurized by feel (but I don't have a vacuum gauge). I was twisting the knobs again and I've concluded that unless I'm going pretty darn fast in reverse I don't see any possible way of the wind or anything locking these. With that said I'm going to put the hub caps on the front and check again next weekend to see if they're locked. My security bolts aren't the right thread pitch so I'll have to use a regular allen key one and try to find something different later on.
 

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4wd light came on within a couple seconds, then I put it in neutral to put it in 4 low and the low light came on as well. I'm just getting ready to head out and retry the 4x4 and vacuum lines so I'll report back in a little bit.
Testing the vacuum lines is to determine if the solenoid is working and none of the vacuum lines are leaking. With that eliminated, you then would need to determine if it's leaking at the inner hub seal. If air bypassing the seals in the hubs, then the auto lock feature won't work. Even though the dash says 4WD, your hubs aren't AUTO locking (so to lock them, you would physically have to get out and put them in "lock").

To check if a wheel is locked or not locked. Simply jack up the front of the truck. Rotate one of the front wheels by hand. If you see the drive shaft that goes to the wheel turning with the wheel. Then it's locked. If the wheel free spins and the shaft is not turning. That particular hub is not locked. The drive shafts to both wheels should turn with the wheels when 4WD is engaged.
 

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Discussion Starter #49
So just as a quick check say in a parking lot where I don't have a jack, I could go under the truck and if the front hubs are not locked then the front driveshaft should spin, but if they are locked (even though the dash is in 2wd) it should not spin, correct?
 

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Correct.

And even if it's in 4x in the tcase, you can try to turn the axle shafts in the knuckle. If the hubs are unlocked the shafts will turn.
 

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So just as a quick check say in a parking lot where I don't have a jack, I could go under the truck and if the front hubs are not locked then the front driveshaft should spin, but if they are locked (even though the dash is in 2wd) it should not spin, correct?
I never tried that. But I think it might be hard to turn those shafts by hand. The idea is to turn the wheel when it's off the ground and see if the shaft rotates with it. If you lock the hubs, even though the dash switch is still in 2WD. You engaged the shafts so the shafts would still turn, but technically it's still disconnected at the transfer case so it would still be 2WD :crazy:
 

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Why do that? You'll be dragging the front axle all the time. The only way I'd do that is if I was in a 4wd situation and my ESOF was leaking (like mine does)
I have had my truck nearly 5 years put around 55K on it, and hand calculated my MPG on every fill up. I have tested it many times and I have came to the conclusion that having the hubs locked makes absolutely no difference in fuel mileage. Also Jeeps and Dodges have full-time hubs so the front axle is always spinning and they last just as long as ours do. Leaving the hubs unlocked for long periods of time can cause the u-joints to seize up. However one advantage of locking hubs is if you ever break something in the front driveline you can unlock the hubs and still drive it.
 

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So just as a quick check say in a parking lot where I don't have a jack, I could go under the truck and if the front hubs are not locked then the front driveshaft should spin, but if they are locked (even though the dash is in 2wd) it should not spin, correct?
That is correct, but if only one hub is locked you can still spin the front driveshaft, so when you do that look at the font axles on both sides to see if both of them are spinning. If only one is spinning lock the hub on that one, and see if the other one spins when you turn the driveshaft.
 

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I have had my truck nearly 5 years put around 55K on it, and hand calculated my MPG on every fill up. I have tested it many times and I have came to the conclusion that having the hubs locked makes absolutely no difference in fuel mileage. Also Jeeps and Dodges have full-time hubs so the front axle is always spinning and they last just as long as ours do. Leaving the hubs unlocked for long periods of time can cause the u-joints to seize up. However one advantage of locking hubs is if you ever break something in the front driveline you can unlock the hubs and still drive it.
I and the accepted laws of physics disagree with you. LOL But we've had that argument before, so let's just drink on it. :shots:
 

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Discussion Starter #55
Well would you imagine that....2 days go by, a little over 300 miles and my hubs are still unlocked! Not the biggest fan of this look, however it seems like it's working.

 
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