Story and image by Martin Pretorius
First, there was four-wheel-drive; then came the differential lock. Of these two mechanical innovations, it was possibly the latter that turned off-roading into a more fulfilling activity: it made it easier for even a novice to make a vehicle climb over seemingly insurmountable obstacles, and it liberated the extra traction that enabled four-wheeling die-hards to push their steeds to greater achievements.
Production vehicles like the Mercedes G-Wagen and Land Cruiser really drove home the advantages of having a plentiful supply of differential locks fitted to your off-roader, but it’s only fairly recently that lockers started becoming standard equipment in mainstream off-roaders. This means that there is still a horde of older (or less well-equipped) vehicles that would benefit greatly from a fairly simple upgrade. As with most things motoring, there are several options available for improving a vehicle’s off-road traction, thanks to a range of aftermarket retro-fit systems.
Would a locking diff turn any four-wheel drive vehicle into a rock crawler?
In an ideal world, yes. However, not all systems are compatible with proper locking diffs. For instance, there isn’t much that can be done to improve the on-demand all-wheel-drive systems fitted to softroaders and urban SUVs − but that doesn’t really matter: their lack of ground clearance usually brings them to a halt long before the electronically-assisted traction management system runs out of talent. So, for the purpose of this article, we will focus on heavier-duty systems: devices that improve the off-road abilities of low-range-equipped 4×4 bakkies and SUVs.
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