4x4s

A 4x4, or four-wheel drive, is a vehicle drivetrain that can send engine power to all four wheels. This arrangement enhances traction on loose or uneven surfaces such as mud, snow, or rock. The term is often used interchangeably with all-wheel drive (AWD), but typical 4x4 systems feature a transfer case and selectable two- or four-wheel drive modes, potentially with a low-range gear for severe terrain, whereas AWD systems are usually always active and optimized for on-road use.

Key components include the transfer case, front and rear differentials, and driveshafts connecting the engine to both axles. A low-range gear multiplies torque for slow, steep, or rough terrain. Some 4x4s offer locking differentials or electronically controlled differentials to maximize traction, especially in off-road conditions. Modern systems may automatically engage or adjust torque distribution.

Historically, 4x4 technology emerged for military use in the early to mid-20th century, with vehicles such as the Willys Jeep and Land Rover establishing the format. After World War II, civilian 4x4s evolved into purpose-built off-road vehicles and later into sport utility vehicles and pickup trucks marketed for recreation, work, and exploration.

4x4s vary from rugged, off-road oriented platforms with heavy axles and long-travel suspension to light-duty crossovers that use a 4x4 drivetrain with more street-oriented tuning. Some systems are part-time and require driver input to engage, while others are full-time. Advantages include superior traction in poor conditions and the ability to crawl over rough terrain; drawbacks include reduced fuel economy, increased weight, and higher maintenance needs. Modern 4x4s increasingly incorporate electronic traction aids, selectable drive modes, and terrain response systems.