In slick conditions, a selectable locker in the rear, locked, in 2wd, often just makes things worse. Your front tires are the anchors, or plows, holding you back. Adding the locker just makes the truck fishtail and wobble about. In dry conditions, the locker may help in 2wd quite a bit.

Now in 4wd, that's when that locker comes alive.

It's not hard to make a sharp turn with a SD and get stuck in the snow with 1 front wheel spinning, and 1 rear wheel spinning. The E-locker will pop you out of that mess perfectly every time. Almost always, one of the rear tires is planted pretty good.

Tried climbing my icy hill last week for testing. 2wd, truck just sits there with the TSC cooking the rear brake pads. 2wd locked, truck just sits there both tires spinning gently as the TSC reduces throttle to only allow the tires to spin a little bit. 4wd, we can get going ok, a little wheel spin, not much. 4wd with the rear locked, no problemo, no wheel spin at all.

Another fun test. Find a perfectly straight, but bumpy gravel road. Where bumps are only on the right side, like potholes. Go extra slow in 2wd open. Then do it again in 2wd locked. Can you feel potholes and bumps on the right side of the truck, tug and pull on the left side? That's another way selectable lockers cost you grip, sometimes.

 

Lockers are a big deal for serious off-road drivers. For example, let's say you were driving up some extremely rocky conditions, and the suspension flexed so much that one rear wheel was on the ground and one was dangling in the air. In this situation all the power (to the rear) would go to the wheel spinning uselessly in the air. Well, traction control would likely keep you moving but it would need a lot of wheel spin and throttle. However, if the locker was engaged, power would be distributed equally to both the wheel in the air and the wheel on the ground, and you'd keep moving very easily.

As I've always said, when the traction available under each tire is roughly the same, a locker doesn't really help. Power always goes to the path of least resistance. If traction is equal, the differential sends power to both sides. Locking the rear end to force that to happen doesn't change much (as you saw in the snow). But for high traction disparities, it helps a lot.

To install this type of locker using an aftermarket like ARB would be very expensive...maybe $1500 or so. Thus, it's a bargain at $395.

 

Does the rear E-Locker engage in 2wd? I don't know.

The reason for the E-Locker is to prevent the effect of an open differential in low speed, low grip situations. Say in heavy snow or mud, it sends drive to both rear wheels so as to increase drive. Once the vehicle is moving there is less need thus it automatically unlocks.

When turning with the E-locker engaged both wheels on the axle are forced to turn at the same speed because the E-Locker locks the individual axles together. To turn the vehicle the outside wheel has to turn faster than the inside wheel or force one of the wheels to slip on the road surface. This is why a true LSD is preferred in normal driving. With the E-locker, both wheels are locked so if you are making a turn on a slick surface, one wheel is forced to break traction and slip. The loss of grip by one wheel when turning could overload the other tire and cause the entire rear end to slide laterally. The average driver is not prepared to deal with such a situation.

 

If you pull out the ****, it will happily engage in 2wd or 4wd. The Raptor is the only Ford which won't allow the locker to work in 2wd. In fact, you can buy an F-150 or Super Duty that only has 2wd but get it with the same locker that 4x4 trucks have.

 

Good to know. I have only used mine a couple of times and that was when engaging 4wd for low speed maneuvering in snow.

I really didn't have a need for 4wd as my truck will spend most of its life on the interstate. I liked the FX4 ride and handling and finding a 2wd truck equipped the way I wanted was proving difficult.