In slippery conditions drive power will be directed to the road wheel with the least resistance. To overcome this problem, the standard Land Rover Defender has a central differential locking system. This is fine in most conditions but doesn’t lock all wheels; the result being that all drive power will still go to one spinning rear and one spinning front wheel, meaning you are going nowhere. A couple of months before the trip we went for an off-roading day to a local venue; it was wet, very wet and whilst son Gavin’s old Series 111 Land Rover managed to get around the course, we struggled to get out of the car park thanks to our weight and spinning wheels (and the Warn Winch failed us again!).
This clearly was a concern for us as we would be hitting some countries in the wet season and were fully expecting to get stuck in black cotton mud and sand; we needed to be able to extricate ourselves without too much effort.
This led to the fitting of an ARB rear differential air locker (you can get front ones as well) that is engaged by switching on a small air pump and then releasing air to engage the locker. This locks the two rear wheels to greatly improve traction. It is difficult to gauge its efficacy because I tended to engage the standard central locking system whenever we were in conditions that might require it, and where the wheels were able to equalise the rotation on a loose ‘road’ surface, and have the air lockers ready to engage for the really sticky sections. We only got stuck twice; once in sand when I wasn’t concentrating, in the wrong gear with no lockers on; and in black cotton mud where traction was lost because the Land Rover bellied out on a rut.
I did, however, have a major problem with this item, necessitating repair in South Africa (see Day 236, 239 & 253) which was very disappointing given the very considerable cost of the system and fitting – not impressed.
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