Who I am ---------- Disclaimer Automotive glossary Four Wheel Drive Synonym: All Wheel Drive Abbreviation: 4WD | Definition Four Wheel Drive: On most cars only one of the axles is driven by the engine. Vehicles which are also moved off-road, as well as for several forms of motor sports, it is necessary to drive on both axles, to allow a (fast) headway also in difficult situations. Preponderantly two systems are in use: permanent all-wheel-drives use a central differential, that permanently allocates the engine power on the two axles and usually disposes of a differential lock; with coupling controlled all wheel drives, one axle is permanently driven, the other one is provided with drive power by a coupling only under certain circumstances or manually. The advantage is mainly the low price. All wheel vehicles need differentials on both axles. All definitions |