I have a 2003 F250 4X4 with ESOF and factory locking hubs. On a previous vehicle, I was surprised to learn that I only got power to one of the front wheels and one of the rear wheels when in four wheel drive. Again, that was a previous vehicle. My questions relative to my current Super Duty are:

If I don’t lock the front hubs, and put this vehicle in 4 wheel drive, am I only getting power to one front wheel?

If I lock the hubs and put the vehicle in 4 wheel drive, how many total wheels am I getting power to?

 

If you have a non-limited slip, or "open" axle in your 4x4, then yes, you're only getting one front and one rear wheel driving when you engage 4 wheel drive, whether you manually engage the hubs or not. If you really want limited slip axles, it's best to buy a truck with them, since it's fairly expensive to add them later. But if you already have the truck, and you NEED limited slip (as opposed to THINKING you need it) then be prepared to shell out some money. But most trucks do quite well without, provided you know the limts.

 

stepping on the brakes a little and providing some drag along with not using full power on an open diff will help as well.

 

If you are interested in an aftermarket product check-out this website:

Randy's Ring & Pinion. The Differential Experts. Auto Parts & Services.

 

If you have ESOF, when you turn the switch, IF everything works right, you have power to BOTH front wheels. If one slips, the other will not get power.

With ESOF you do not need to manually lock the hubs. IF everything is working right.

The front differential is an "open" diff. So, if one wheel slips, the other will lose ALL power.

Being very careful on the go-pedal is a good idea

 

A long time ago Ford built trucks that put power to all 4 wheels when 4 wheel drive was engaged. They were very hard to turn when in 4 wheel drive but were used by the power companies around here since they just drove straight down the lines. But the way it is now works the best by pulling 3 wheels. LS could use some work though.

 

I assume by "don't lock" you mean leave on AUTO... The ESOF system locks the hubs for you, just like if you had gotten out and turned them to LOCK.

There are a few different combinations of differentials that you can play with. The most common, and probably what you have is:

Open front, LS rear. This will guarantee power to both rears (unless you overtorque the LS) and one front (the slipping one).

you could go for an LS front, LS rear setup which will guarantee power to all four unless you overtorque the LS...then they act just like opens

Your old 4wd sounds like it had open front and open rear... guaranteeing power to one front and one rear wheel...

While possble, a LS front and open rear setup is odd. The only advantage I can see is that you would save some tire wear on the highway having an open rear, and then you get some extra oomph by getting power to both fronts when clicked over.

None of these combos have even touched on actual locking differentials.

There are four types of lockers:

1) locked always (spool) unless you are a drag racer...don't
2) locked w/turn release. When the wheels see opposing friction forces, the diff releases for the turn, usually making a clicking sound as the locking teeth pass eachother. These will wear out eventually.
3) LS with solenoid lock. When engaged, acts like a spool, when disengaged, acts like an LS
4) open with solenoid lock. When engaged, acts like a spool, when disengaged, acts like an open

The Best 4x4 combo that you will find anywhere (but pricey) is to have an open solenoid lock in front, and an LS solenoid lock in back.

 

There's also the poor man's selectable front locker:
If you have manually lockable hubs, lincoln lock the front diff (weld the spiders). Then lock only ONE hub most of the time, especially when manueverability is needed. And then lock both hubs when ultimate traction is needed.
If you drive with your brain engaged, it is better than an open diff. The wheel that is locked is always getting power and driving forward, regardless of traction variances between the wheels. With open diff, the wheel with least traction gets all the power - and the wheel with more traction gets none. If you select your lines knowing which tire is locked and pulling, you can do much better than if you have open or even LSD diff! And if the only line favors the unlocked wheel, hop out and lock that side instead. For foul weather driving, it is most likely you want to lock driver's side as it is usually ice on the passenger side shoulders that cripples an open diff.
Yes, it does put a bit more strain on driveline components than an open. But less than a solid locked. Our Dana's can take it just fine if you're not stupid with the throttle.

And a creative guy with ESOF hubs could probably figure out some cab mounted pnuematic valving to let him select which hub gets vacuum and locked and which does not.

 

Thnx guys for the information and input. I was not looking to make modifications. I just wanted a clear understanding of what I have and it sounds like I have power to one fron t wheel without locking the hubs (provided that wheel doesnt spin) and power to both when it is locked. Thnx again.

 

Clarification:

You don't have power to any of the front wheels unless the hubs are locked "AND" in 4wd.

 

this is impossible...

hub unlocked = no power to wheel

both front hubs unlocked = no power to the front

 

I am confused. I seem to be getting conflicting answers....from one post above

"With ESOF you do not need to manually lock the hubs. IF everything is working right." Other posts indicate if I dont lock the front hubs and simply use the ESOF to put it in 4 wheel drive, I have no power to the front wheels.

Accordingly, without locking the front hubs, do I have power to the front wheels or not?

 

The earlier post is correct. If the ESOF is working correctly, when you engage 4wd from the cab of your truck, the hubs lock automatically. The hubs being locked, however, in OUR trucks, is only going to get you power to one wheel at a time because we have what is called an OPEN DIFFERENTIAL. An open differential works by applying power to the wheel with the least resistance, making the truck behave more friendly on the road. But, if you are in the mud, the wheel that is spinning is the one with the least resistance, not the one that has traction. What most of us have in the rear of our trucks is a LIMITED SLIP DIFFERENTIAL. A limited slip works by providing power to the slipping wheel, but NOT both at the same time. This is BETTER than an open differential, but it still only applies power to one wheel at a time. The BEST kind of differential for offroading is a LOCKED DIFFERENTIAL. There are many different kinds of locked diffs, but essentially they all do the same thing, which is apply power to both wheels at the same time. And when I say "both wheels," I mean either both front wheels or both rear wheels.

So, the answer to your question is, when you engage 4wd from the cab of your truck, theoretically the front hubs lock, giving you power to ONE wheel on the front of your truck (whichever one has the least resistance because its an OPEN differential). The rear continues to act as it would in 2wd, which either means it acts like an OPEN diff or a LIMITED SLIP diff, depending on what your truck is equipped with. If your truck has the FX4 package, it most likely has the LIMITED SLIP, otherwise it's hit and miss with the standard 4x4's.

My suggestion to you, is that if you know you are going to need the 4wd, get out and lock the front hubs manually because the ESOF in these trucks has a tendency to fail pretty early in the life of the truck - which is why they give us the option to lock them manually.

Just to throw another wrinkle in the equation, I disconnected the power to the ESOF line for the front hubs on my truck so I can put the truck in 4-LO and have the lower gearing that it provides and not engage the front hubs. Essentially a 2-LO. This comes in handy moving my 5th wheel around the yard or on pavement where it is not a good idea to be in 4wd.

I hope this clears things up. If that last piece about 2-LO confused you, just ignore it. It's not essential to the explanation of how YOUR truck works.

 

Robert,
Good Explaination...Thnx
CT

 

When talking about an open differential setup...I've read a few posts talk about only one wheel having power. The way I have it pictured in my mind, is that both wheels have power, when they are traveling straight ahead and in good/equal traction. It's only when one wheel has different traction than the other... and in that case... the amount of power applied to both wheels, is limited by wheel that is slipping. i.e.. the point at which the wheel slips is where no more power goes to the non-slipping wheel.

I guess what I'm trying to say is that I always pictured it not so much as "only one wheel having power" but rather one wheel, the one with the least traction, is the limiting factor in the amount of power being effectively applied to the wheel.

So, in the case of an open differential... *if* you had the ability to brake one wheel versus another, you could essentially choose which wheel to funnel power to, is that right?

Forgive me for jumping in, but as the original poster also said....I just like to understand things as completely as possible...and in terms that make sense to me.