My experience using a 4x4 is relatively limited and I don't understand when it would be beneficial to use the electronic locking differential (ELD). (See my signature for what my new F150 came with.)

I used to have a 1990 Ford Van that had a 4x4 conversion done on it. (I loved that van--which I never sold it.) When working on a survey project off road I could get out and lock/unlock the hubs. So it was either 4x4 or not. No other choices. It took care of me just fine each time I used it.

Now, with the ELD on my new XLT, I'm not sure what advantages it provides verses just using 4H or 4L alone. I tried searching but didn't turn up what I'm looking for. Any advice is welcome.

 

My advice: Don't use it unless you have to. Don't ever use it on anything but loose gravel, snow, mud/dirt. Basically, wherever the truck can slip, since it locks the rear wheels at the same speed.


Other than that, don't put your truck in 4H or 4L unless you're on slippery stuff.


-John

 

Your F-150 has an open differential on the front and rear when in 2WD or 4WD. This means that whichever wheel has the least resistance gets the power. So if your rear left tire is on ice, it will be the one that gets most/all of the power. Even if in 4WD, the wheel on the front or rear that has least resistance gets the power.

Most every modern vehicle combats this with a traction control system that basically just applies the brakes on the wheel that is "spinning". This effectively makes the wheel that hopefully has traction (not on the ice) get the power, since it now has the least resistance.

This open differential setup is what allows the truck or car or whatever to turn in a circle without the axle binding and exploding into glorious metal fragments.

A front/rear locker closes that open differential setup making both wheels spin with roughly equal power, regardless of which one is on ice or whatever. It's great when dealing with very deep snow or mud or hill climbing or whatever, it keeps all the tires on an even playing field and keeps you moving forward.

Turning though, if not on a very slippery surface, with the rear locked can lead to bad things. I think the F-150 has some safeguards in place to prevent total disaster, but it still sounds pretty awful.

So in summary, it's a great feature that unless you are heavy duty offroading weekly you may only really use a handful of times during your truck ownership.

Edit: Before someone comes in and gets combative with me on the above as often seems to happen around here, the above is just based on what I have learned about 4x4 systems, lockers, etc, and I am not a mechanic by trade so I may be a bit off on some of it, but your van has basically the same 4x4 your F-150 has. If you ever watch a video of a 4x4 or AWD vehicle stuck in snow without a traction control (braking) system, you will usually find that only one wheel at the front and rear actually spins.

 

your pretty spot on vulnox

 

To answer your question as to *when* you would need to use it - probably never, for most drivers.

Backing a trailer up a low-traction surface.
Serious off roading.
Some seriously slippery snow.

 

Very simple and short: the ELD should be used when there is a substantial difference in traction between the two wheels (this infers that one will be able to slip, preventing driveline damage).

The most common use would be parking on the side of the road, where one wheel is on the pavement and the other is in mud. Engage the ELD just until the wheel in the mud hits pavement.

ELD is *not* a 4WD replacement. Do not engage it in situations where both tires have minimal traction (for instance, on ice) or you'll have a very bad experience.

 

Can you elaborate on this? I thought this would be exactly when I would want to use it.

 

Thanks, vulnox, for the great explanation. Sounds to me like, as a general rule, it should only be used when 4H or 4L is not getting the job done...use it temporarily to get out of a situation. Then turn it off.

 

From the Owner's Manual:

"ELECTRONIC LOCKING
DIFFERENTIAL (If Equipped)
Note: The electronic locking differential is
for off-road use only and is not for use on
dry pavement. Using the electronic locking
differential on dry pavement will result in
increased tire wear, noise and vibration.
The electronic locking differential is a
device housed in the rear axle that allows
both rear wheels to turn at the same
speed. The electronic locking differential
can provide additional traction should your
vehicle become stuck. You can activate
the differential electronically and shift it
on the fly within the differential operating
speed range. The differential is for use in
mud, rocks, sand, or any off-road condition
where you need maximum traction. It is
not for use on dry pavement."

 

My experience, from long ago in icy Alaska, is that when both rear wheals are spinning there is nothing to keep the rear of the truck from fishtailing around and getting in front. Results vary depending on how fast the truck was traveling.