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Eaton Harrop ELockers

Diff lockers are nothing new. They have been around for many years, providing the ultimate increase in traction. The way the lockers work though, is continually being worked on. Today, I’d like to introduce to you Eaton Harrop ELockers.

Differential lockers

Need more traction?

What are diff lockers?

Before I go into Eaton Harrop ELockers, we must first look at how a differential works. For most four wheel drives, open diffs are standard. This means that the axles on either side of the differential are not locked together (in other words, both wheels can rotate at different speeds, which is required for going around corners!).  The power from the engine will always go to the wheel on each differential with the least resistance, which is not ideal when four wheel driving.

When we are off road, this usually means that the wheel with all of the weight on it (and the most traction potential) sits there doing nothing, whilst the other wheel on the axle spins like crazy. In a 4WDing application, often one wheel on each differential will spin, and the other 2 will not. This is known as being ‘crossed up’ and results in your car not moving at all!

A locker simply locks both axles on the differential together, so the wheels are forced to rotate at the same speed. This ensures that regardless of how much weight your tyres have on them, the wheel will continue to spin.


LSD’s, or limited slip differentials make use of a clutch between the two axles. The idea is that when one wheel stops driving, the clutch attempts to make the other wheel continue to drive. For most Toyota’s, the LSD’s are worn out within 20,000km and are virtually useless. Nissan make great LSD’s which work quite well, but an LSD will never be as good as a locker.

Types of lockers

It’s well known that a locker (or 2) will make your vehicle considerably more capable. However, as I mentioned above, there are plenty of different types; air lockers, electric lockers, auto lockers and mechanical lockers.

Air lockers are engaged via compressed air, and the most well-known are made by ARB and TJM. Auto lockers engage automatically when they detect wheel slippage, and are made by a number of different manufacturers (Lokka, Detroit and Lock Right).

Electric lockers are engaged with the use of an electromagnet. They require 12v power, and that’s it!

Why fit lockers?

The primary reason for fitting lockers to a 4WD is to maximise the available traction. There is no point having huge tyres, a big lift kit and a massive engine if you aren’t able to translate this into traction. By having twin lockers, all 4 wheels rotate at the same speed, and give you the most traction possible.

Differential lockers

Power without traction isn’t going to help

It would seem then that the only need to fit lockers is for extreme four wheel driving, but this isn’t quite correct. Lockers allow you a significantly greater control of your vehicle. When you approach an obstacle, there are a number of ways you can attack it:

–          Idle up slowly and see if your vehicle makes it. If it doesn’t, you need to back down and try again, which isn’t always easy or safe.

–          Give it a boot full and hope for the best. This often works, but will eventually lead to something breaking.

–          Engage the locker (s) , and drive up knowing you have the most possible traction. This is the best choice as it looks after your four wheel drive and the tracks, whilst giving you the best chance of getting through the obstacle.

Sure, you can do without lockers, but in many applications to overcome the lack of traction you must attack the obstacle with more speed. This is ok in some cases, but it will inevitably put more stress on your vehicle and lead to breakages eventually.

Eatons Lockers

Impossible hill climbs are made possible with ELockers

With lockers, you can approach any obstacle slowly and carefully, knowing that you don’t have to worry about wheels sitting stationary. This is especially important on hill climbs, where a loss of traction can cause significant problems!

Eaton ELockers

Eaton Harrop ELockers have been designed to suit a number of 4WD vehicles, and new models are being brought out on a regular basis to suit our ever changing 4WD industry. They are simple, easy to install and have been proven in hundreds of four wheel drives, from the family touring vehicle through to competition spec winch vehicles.

E locker switches

Instant traction buttons

I installed front and rear lockers to my 80 Series Land Cruiser, and have been absolutely blown away by their performance. I know that when I get to a difficult situation, rather than using momentum to overcome the obstacle I can put one (or both) lockers on and drive through it in a much more controlled manner.

Harrop have been in Australia for 57 years, manufacturing and designing everything from superchargers through to race car driveline parts. They have a solid reputation, and partnered with Eaton to bring the ELocker to Australia.

Eaton are even bigger, and have been manufacturing in the Aerospace, Automotive, Electrical, Hydraulics and many other industries for well over 100 years. Together, the Eaton Harrop ELocker has a very solid foundation!

Advantages of the Eaton ELockers

Eaton Harrop ELockers are simple. They have two wires running to the differential, and a switch that activates them seamlessly. They are extremely quiet (when I fitted them to the differential, we tested them out of the vehicle, and had to do it twice because we couldn’t even hear them engage!)

Traction via an electronic locker

Simple, traction on demand

The simplicity makes it easy to repair should anything go wrong in the bush; if a stray stick or rock break your cable in half, you simply join a new section in. The plugs are all completely dust and waterproof, and the unit is built with some serious engineering thought behind it.

Eaton lockers don’t require the use of a compressor, which means you don’t have to run one to engage the locker, and you don’t have to plumb it all up.

How much are they?

Eaton Harrop lockers retail for around $1500 each, depending on the make and model of your vehicle. Fitting is on top of this, and is usually around $400 each, or you can do it yourself.

Can I fit it myself?

If you are familiar with differentials, fitting Eaton ELockers should be no worry. However, Eaton recommend getting a differential specialist to do the installation if you have never installed a diff before. Each locker comes with extensive instructions, and it’s just a case of removing the differential, swapping the differential carrier, replacing the bearings, checking the backlash, drilling a hole in the differential housing and completing the wiring to the dashboard (where your switches are mounted). This will take at least a couple of hours per differential.

In my case, I was comfortable removing the differential, but less comfortable replacing the carrier and bearings, and got Perth gearbox differential and clutch center to install the lockers. They did a great job, and then we tested them and installed the differential back in place.

Front or Rear lockers?

This is one of the questions that you can spend hours arguing about. If you have an LSD that works well, it is a good idea to fit the ELocker to the front of the vehicle. However, a locker will work more effectively on the rear, as you mostly need them when climbing up hills, which puts all of the weight on the rear of the vehicle.

Confidence through lockers

How confident are you?

Where can I get them from?

Harrop distribute their ELockers through Terrain Tamer, Harrop Traction Dealers and Opposite lock. There are plenty of these scattered across Australia. You can find a full list of dealers for the ELocker here.


If you are looking for solid, simple and reliable lockers, then the Eaton Harrop ELocker is well worth buying. I’ve used mine a number of times now, and have been very impressed. Just flick the switch and you have instant maximised traction.

Lockers by Harrop

It all pays off!

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3 comments… add one
  • Kayne Moore August 10, 2015, 10:11 AM

    Do they make a front and rear elocker for 2000 model Rodeos 2.8L diesel

  • Aaron at 4WDing Australia August 11, 2015, 6:48 PM

    Hi Kayne,

    I’m not too sure mate, but if you give one of the resellers a call they will be able to give you an answer over the phone. You can find them here – https://www.harrop.com.au/dealers/


  • Kayne Moore August 11, 2015, 7:43 PM

    Ok thanks

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