Isuzu Motors South Africa says an optional mechanical diff-lock is now available for both variants in its MU-X seven-seater SUV range.

So, how much will this Eaton MLocker mechanical locking differential cost you? Well, the local arm of the Japanese firm says it is available – for both the 4x2 and 4x4 derivatives – for an extra R11 500.

Isuzu SA says the MLocker functions as a light bias limited-slip differential during “normal driving conditions” and as a full locking differential when traction conditions become "tricky".

The diff automatically locks to deliver added traction on surfaces such as wet tarmac, gravel, mud, dirt and sand. When a low-traction situation causes a wheel speed difference of 100 r/min, a flyweight mechanism opens to engage a latching bracket.

The stopped flyweight then triggers a self-energising clutch system, forcing a cam plate to ramp up on a side gear. This continues until both axles turn at the same speed (that is, full axle lock), which prevents further wheel slip. Unlocking occurs automatically, allowing the differential to resume normal operation.

Isuzu SA says the MLocker “does not interfere” with existing vehicle safety systems as it automatically disengages from speeds of 30 km/h.