Just as 4WD High locks the front and rear axles together, the rear diff lock connects the rear end side-to-side. That means ...

Some cars come equipped from the factory with locking diffs, usually on the rear axle, but more hardcore models like the Mercedes-Benz G-Class can be specced with up to three locking diffs.

Jeffrey D. Gaskin delivers a guide to four vehicle systems that are key to gross axle weight ratings and gross vehicle weight ...