Truck: 2006 F-250 FX4 Lariat, 6.0
Mods: bulletproofed, 6" lift, 35x12.5 aggressive MTs (really should get bigger tires...they look too small)

OK, I have not had much opportunity to use the 4wd on my truck since I got it 4 months ago, I would lock the front in when I get to the hunting lease, but that is it.

I have determined, I think, that the auto hubs are not working as intended.

We have a nice little cold snap, with ice and snow coming tomorrow, and I have to go into work, so I figured I would check out the 4wd today to make sure it worked.

I pulled into my very wet yard, at idle, rear tires slipping a bit, got stuck at about 50 ft. Put it into 4 low (light came on correctly), put it in drive, came off the brake, and rear tires where still slipping, no movement out of front tires. Got out, locked the front in manually, and she crawled out, albeit leaving behind a bit of a mess....7,000 lbs in a water logged yard and all...but did not slip tires while locked in.

So, conclusion, auto hubs not working, manual locking works as intended.

Now for the questions part:
as I was going down the driveway when I went to pull into the carport (with front hubs locked and in 4L) the front started binding really bad when near full lock to the left, same way my mud truck does that has spools in the axles.

I unlocked one hub, and she turned just fine still in 4wd, one hub locked.

I took it out of 4wd and re-locked both hubs, and she turned just fine. This was with the hubs still locked.

I'm a bit confused, as I have only had binding happen with spools, in which case, it should happen any time both hubs where locked, 4wd engaged or not, as the binding is across the tires, not the T-case.

from what I can gather, it means that it has to have a locker (or a limited slip where the clutches are stuck?), but for some reason, it is applying equal torque to the outside tire while not letting it spin faster than the inside.

does this make sense? Is this how they all work, at least when locked in?

Lastly, can I drive the truck safely, without compromising breaking something, with both hubs locked but the truck in 2wd, and put it in 4H only when crossing bridges/overpasses?

what about just driving it in 4wd with locked hubs the entire way? will the binding be enough to break something, hubs or diff most likely?

Would this happen with the hubs in auto provided that the auto hubs actually worked correctly? (or are they, and they just require more speed and/or engine or axle RPMs?)

TL;DR: getting binding on pavement with hubs locked in manually, but I need 4wd tomorrow on the roads due to essentially guaranteed icy roads and it seems that my autos are not working.

on edit, when purchased, I had been told that the previous owner had had some work done to the diffs, I do not know what exactly, and had had the tranny replaced

 

From the OP;
I'm a bit confused, as I have only had binding happen with spools, in which case, it should happen any time both hubs where locked, 4wd engaged or not, as the binding is across the tires, not the T-case. You are really confused
Binding is not across the wheels. It involves the t-case and all 4 wheels

from what I can gather, it means that it has to have a locker (or a limited slip where the clutches are stuck?), but for some reason, it is applying equal torque to the outside tire while not letting it spin faster than the inside.
That's because all 4 are locked up. LS clutches never stick.

does this make sense? Is this how they all work, at least when locked in?
Yes.

Lastly, can I drive the truck safely, without compromising breaking something, with both hubs locked but the truck in 2wd, and put it in 4H only when crossing bridges/overpasses?
Yes, good idea.

what about just driving it in 4wd with locked hubs the entire way? will the binding be enough to break something, hubs or diff most likely?
Yes, never do that unless you stay in a straight line but still not good because even tire differences can affect in binding.

Would this happen with the hubs in auto provided that the auto hubs actually worked correctly? (or are they, and they just require more speed and/or engine or axle RPMs?)
Same as manual lock symptoms.

TL;DR: getting binding on pavement with hubs locked in manually, but I need 4wd tomorrow on the roads due to essentially guaranteed icy roads and it seems that my autos are not working.
You can drive on icy roads in 4wd, it's the turning on dry pavement especially at low speeds that isn't good.

on edit, when purchased, I had been told that the previous owner had had some work done to the diffs, I do not know what exactly, and had had the tranny replaced[

Are you grasping it yet?
The front axle acts the same as the rear when locked, the problem lies when the front shaft tries to spin at a different speed than the rear shaft.

 

The Auto Hubs not locking could be due to a vacuum leak. I don't think it would be different for the 6.0, but an easy test atleast with the 7.3;
Turn the air on and set it to vents.
Turn the selector **** from 2wd to 4wd.
It could take a minute or two, but if the air shifts from the vents to the defroster, you have a vacuum leak some where. commonly the rubber hose that runs to the back of the hubs, or the rubber seal on the hub locker.

 

It's binding cause you're driving in 4 lo when fully turning front wheels while pulling into carport.

 

yes big al

 

I guess that this is my mistake, I meant to also put in a qualifier about how on my spooled truck, the tires do the same sort of hop/bark like what this truck was just doing. I was not sure if it was a binding of the driveline, or the front tires not wanting to spin at differant rates.

But I get it now what it is that was the issue. Good to know that it is in fact working properly. I take it that that is why AWD vehicles, or at least some, have a differential in the T-case as well then.

As far as the auto hubs, I had considered the vacuum leak idea, but have not explored it yet.

I will take note and check to see if I can determine a leak by the method mentioned tomorrow. I am pretty sure (I'm hoping at least) that it is something simple like a vacuum leak.

In this case, I will lock both hubs tomorrow before I leave, but keep the truck in 2wd. As the only bridges I have to cross are short and straight, I will put it in 4wd temporarily as I cross them, then turn it back off after I've crossed.

There were over 200 wrecks on Friday in town when we had a smaller freeze....I would rather not be on the list of wrecks for tomorrow and Wednesday's weather.

Thank you all for the help, have a good evening.

 

Some binding when in 4 wheel drive and you have the steering wheel at full left or right lock is normal.

 

It'll be OK to leave the hubs locked in 2wd on your drive. It'll only cost a small amount of fuel milage maybe not even noticeable. As said before the binding is normal on pavement when turning in 4wd as all 4 wheels need to turn different speeds but they can't since the front and rear axles are locked together. That's exactly why awd vehicles have a center diff.

Fwiw I lock my hubs on my manual 4wd truck before a winter storm and unlock when the roads are clear. I also lock them once a month or so year round for a 15 mile commute to work just to let everything up front can get some lube spun onto it.

 

And this is one of the reasons I love Ford for putting manual locking hubs on their trucks to this day.

 

I leave my plow truck hubs locked all winter with no issues. When in tight spots or making hard turns I just drop it in 2. Or when I'm pushing big lots I just leave one locked for turning hard. Id say in the spring it's time to pull them apart and replace the seals or go with manual hubs.

 

Regarding crossing iced bridges- the best thing to do is to do nothing that will make your tires change from their current direction or speed. Ideally, continue to cruise without accelerating or decelerating or changing direction, that is, maintain current speed and direction. The act of shifting into 4 wheel drive may actually be worse, if you have the habit of taking your foot off the accelerator, like many habitually do while shifting.
Of course, conditions like curves, traffic and potholes make this impossible. Being in the wrong place at the wrong time sucks.

 

Wise advice. 4 wheel drive won't help you if you run into a patch of ice. DO NOTHING. No pulling it into 4H, no throttle, no brakes, no steering, until you're out of the ice. If the ice goes for a long time, try to see if there is any snow on the shoulder where you can get some traction. Slowly drive down the shoulder until you can get away from that road and find a place to park.

For examples of the wrong thing to do, just browse the online news for what happened in Atlanta for the past few days.

 

Around here i've noticed a couple of things. First, every one is quick to lock up the brakes when they start to get a little loose. Usually if you only back off the gas as soon as you feel yourself start to slip, you'll straighten back up (depending on speed). Next, It took me a few seconds to figure this out on my own the first time it happened to me. With a rear wheel drive vehicle, when you try to brake lightly on ice (most of the braking force is applied to the from wheels) the front tires will come to a stop while the rear is still trying to push you forward and will start to kick off to the side. Pop it in neutral as you stop and you'll fix that problem.

 

when did they start with auto hubs and if you have manual lock switches in your front hubs...do you have auto hubs?

what is gained by locking the hubs while driving 2wd

if you have a floor shift with 2wd, 4wh and 4wl as well as manual front hubd locks...how would you know you have auto hubs?

the only light on dash activity I see is when I use the floor shift. i see no light on dask activity if i switch from lock to unlock on the hub

and yes, when hubs are locked, I get binding on sharp turns on pavement.

also, tow mode does not seem to work in locked 4Lwd

other than that, in 4WD L, with hubs locked, I would drive my truck thru anything...if i can't make it doubt much else can.

 

OP; Don't switch the T-case into 4wd when you cross a bridge! You will only need it if you stop and need to get going.