THERE’S NO argument that 4WD differential lockers transform a 4x4’s capabilities, but the big argument is whether to put them in the front or rear diffs, or both. This depends greatly on the vehicle type and intended use, so there’s no correct answer.
The number one argument for not having a manually operated diff lock in the front of the Tonner – which sports a GQ Patrol chassis, suspension and diffs – is the loss of steering the instant the locker is engaged. Given that, a manual locker is in the rear diff and an auto locker (a LOKKA from 4WD Systems) is in the front diff, and I should get more use and superior workings from this combination.
The auto locker in the front diff can be used all the time without sacrificing steering ability, and it helps the Tonner crawl through pretty much any obstacle. For extra assistance I can flick the rear TJM Pro Locker into operation.
4x4 gear: What are automatic differential locks?
The LOKKA is mechanically (automatically) operated via cams, springs and pins to return an extremely sensitive unlocking system, and it needs no air or electrical lines, no switches to operate and no driver input as to when they can or should be used.
The two forces that automatically engage and disengage them are engine-driven forces and ground-driven forces. The former keeps it locked as you supply power to the wheels; the latter allows for unlocking and differentiation as you back off the power to allow unlocking, provided no wheel slippage is registered. They even work (stay locked, if needed) when traversing downhill under engine braking
There is, however, a slight loss of turning circle and slightly heavier steering that many users may not even notice, especially in this day of power steering. The advantages far outweigh this and it’s nothing like the losses a manually operated locker will induce.
The LOKKA has worked in all off-road situations by keeping both front wheels turning, with 50/50 power being delivered when a wheel lifts from the ground. Even when excessive power is causing potential wheelspin the LOKKA manages to keep both wheels supplying drive equally.
Follow Mark Allen's Tonner project at The Tonner Files
Instead of allowing the wheel with the least resistance (ala, an open diff) to spin, drive is delivered equally to both front wheels while keeping the Tonner moving; this is the ultimate goal, along with less track damage given less wheelspin.
Given it costs about a quarter the price of a manual locker (of any brand), is much easier and faster to install, doesn’t require an air compressor or electrical line, and requires zero maintenance, the LOKKA is a winner (almost) all around. It’s almost a winner as you lose a little turning circle (about one metre, in my case), there’s a slight cam noise at times, and you can’t turn it off … ever.
While that last point mightn’t be an issue for most drivers, you do lose the option of high-speed, long-distance gravel driving without the front locker engaged. Of course, I can still do that style of driving with the LOKKA. You need to ensure tyre pressures are equal and overall tyre diameters are the same, which can slightly upset the workings of the locker. No additional maintenance is required and standard diff oil is used. Plus, it comes complete with a three-year unconditional warranty in Australia.
The LOKKA is the best value-for-money diff-lock on the market and will transform how your vehicle tackles almost any off-road obstacle.
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Available from: www.4wdsystems.com.au
RRP: $425 (plus $25 delivery Australia-wide)
We Say: Great kit at a bargain price