Wrong. A rear locker is much more usable, as it's easier to control the vehicle in precarious situations. The vehicle is extremely difficult to steer with the front locked and often pulls the front places you don't want it to go with the front locked. If you only have 1 axle locked, rear is the way to go. There's a reason tons of 4x4 vehicles come with ony a rear locker, and none come with only a front.
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You can argue with the manufacturer then... Here's right from the Lokka website under the FAQ's.
"Q10. Which end should I fit first? (if buying one)
This is dependent on the vehicle, its existing differential types, the type of suspension system, LOKKA model availability and the type of 4x4 driving you do.
However, often the front is the first choice.
If the vehicle is an IFS (Independent Front Suspension) model then the front fitment will result in the greatest increase in 4x4 ability. This is because many IFS vehicles have very limited suspension movement (hence limited wheel travel and articulation) resulting in easily lifted wheels and total loss of front traction. Fitting a LOKKA to the front will solve this serious deficiency.
If a vehicle has a good quality LSD in the rear, then a front fitment will obviously provide the best total traction ie. one locker and one LSD is better than one locker and one standard differential.
If a vehicle has a poor quality LSD then the issue becomes less clear and personal preference or ease of installation often become the more important criteria. However one LSD and one locker is still a better choice - if that is possible.
If the vehicle is a constant 4x4 then a rear fitment may be the easiest solution from a fitting perspective, but may not be the best solution from a traction perspective.*
A front fitment will actually yield the greatest improvement in off road ability. This is because, most vehicles require the increase in traction (that a locker gives) when hill climbing. Under hill climbing conditions, due to the angle of the vehicle, the rear wheels are carrying a much greater weight (weight transfer) and the front wheels are therefore carrying a lessor weight and tend to break traction more easily.
Once one front wheel starts to spin, the other front wheel stops turning and the front differential ceases to provide traction. At this point all power load is transferred onto the rear wheels as if it were a 2x4 and due to this increased load, the rear wheels are encouraged to spin and the vehicle stops.
If you can solve the problem of the front wheels losing traction, you have solved the traction problem.
Another advantage is that on road there are no changes to normal driving characteristics – assuming it has Free Wheel Hubs or a Disconnect Mechanism,
* Q10 d. - Extra info
A couple of things to Note: the front diff lock (any type) will give the greatest advantage off road, rather than the rear, assuming most vehicles have greater problems going up hill rather than down.
Two are better than one, but one in the front is better than one in the rear.
This is due in part to the transfer of weight onto the rear wheels, thereby providing greater 'natural' traction as the weight pushes the rear wheels into the terrain. The steeper the slope, the greater the weight transfer.
In addition the front wheels usually have less wheel travel than the rears, so they tend to lift off the ground as the rear drops into holes. As soon as they do, the drive load is rapidly doubled on the rear wheels, as all the front drive is lost to the wheel spinning in the air or on the loose surface, and the front wheel still on hard ground has no drive.
All the load of moving the vehicle is on the rear wheels. The rapid transfer of this load encourages the rear wheels to break traction - forward motion is stopped.
Also remember the front wheels get to the worst part of the track first - assuming you are going forward. The loose gravel, the sandy bit, the tree root, rock ledge, the slippery mud etc etc all these will get one front wheel spinning first, then the other front wheel not being driven, the load on the rear wheels rapidly doubles. The resulting rapid transfer of load encourages the rear to break traction again - forward motion is stopped.
Putting any locker into the rear does nothing to stop the front losing traction, it just makes the vehicle a lot better 2x4, better at pushing from the rear. Even if you can only keep one wheel driving at the front, you will probably have three wheels working and spreading the driving load over the greater surface area of three tires."
