Nope. The differential gets its name from how it allows speeds to differentiate from each other. It allows the inside wheel to rotate slower than the outside to prevent the binding. That is literally the purpose of it, regardless of 2/4wd configuration.

 

Alright, well I'm definitely confused, why do they always warn about not running in 4hi on dry pavement as it will cause drive line binding?

Other than the obvious fuel cost, why would you then. Not just run 4hi everywhere?

 

Because the differential isn't 100% foolproof and can cause binding in extreme situations. Bear in mind, this 4A stuff is fairly new tech. The TOD t-case is a great way to have both AWD and 4WD when needed.

 

Ok, so would you say that this TOD tcase isn't going to behave exactly the same as a regular one, even when in 4hi?

 

I have no idea what you're trying to say.

 

I'm not sure all this is true. If you're in 4H on dry pavement, it will bind up pretty easily, you can tell the first little turn you make at even the slowest speed. And 4A is not AWD the way it is usually defined using the diff, it is an attempt at automatic in-out of 4H using ABS data, using the transfer case. (I'm not a fan) IDK what the "AWD" mode on Harley models does exactly, if it is the same as 4A or not.

 

No, Lockers or locked axles are what causes the binding when turning. Most 4x4 vehicles don't come standard with any kind of locker and they can turn freely on a hard surface, the old *****'s jeeps are a good example. OTOH some cars, particularly those set up for drag racing are only 2 wheel drive but still use a locker in the rear axle to get the absolute most traction.

In the Ford trucks you could get 4x4 trucks that didn't have (standard) lockers or FX-4s that included lockers.

All of that said, there are different types of lockers and some are manually controlled, some are electronically controlled (like the FX-4s), and some like Ford's new 4A are controlled automatically.

Four wheel drive (which is really just means 2 driven axles and not necessary all four wheels being driven) vs 2 wheel drive and the subject of lockers are really two different things.

FYI, if you take a look at most four wheel drive vehicles such as the old ****** jeep, you'll see that both the front and the rear axles are open carrier designs, which means that if one wheel is off of the ground or is slipping due to being on say, mud, then all of the torgue goes to that wheel and there is no traction from that axle. But since in 4x4 mode, both axles are being driven most of time you still get traction from the other axle. But if you're in a large mud hole or on ice or if one wheel on each axle is off of the ground, then you won't have ANY traction. That's where lockers come into play, adding a locker to the one axle will guarantee that both wheels on that axle are being driven so increasing your chance of having traction from that axle. Add a locker to both axles and now all four wheels are being driven and even if three of them are slipping due to mud, ice, etc, then you still have one wheel providing traction.

 

Wow. I just read all of these responses and I am confused...but only about their answers.

I have 4A on my F150 and have had 4x4's for 35+years. Understand that with this transfercase, you CAN drive on hard pavement in 2H and 4A but not 4H or 4L. In those last two positions, the case will bind just like any other conventional case. Lockers make no difference.

If yours does not bind white turning on hard pavement in 4H or 4L, I suspect that you have a failing IWE.

I hope that answers your question .

 

I am trying to determine what the operational differences are for a truck with this TOD tcase is Vs like the regular tcase on the XLT model for example.

As far as i can tell from this thread, the difference should only be the following;

1) 4a is an option, which locks the front hubs and then allows the computer to control whether the clutch in the TOD tcase to provide power on demand to the front driveshaft
2) Even in 2hi, with the hubs unlocked, the TOD tcase will still end up driving the front driveshaft through oil wash (does the regular tcase do this as well?)
3) In 4hi, the TOD tcase should operate exactly like the regular tcase and provide the same results of binding when turning on dry pavement.

Any corrections to be made here?

 

Would you say that the binding on dry pavement in 4hi, feels similar to the binding you feel on dry pavement in 2hi with the rear locker engaged?