Off-Road Driving Tips: Everything You Need to Know About Four-Wheel Drive Systems

The engageable 4WD system, or on-demand 4WD, allows you to activate four-wheel drive when needed. When 4WD is not engaged, the vehicle behaves as a two-wheel drive (2WD), with all torque sent to the rear wheels. Driving in 2WD significantly reduces fuel consumption on the highway. Vehicles with engageable 4WD should be driven on the road in 2WD only to avoid transmission stress. When these systems are switched to 4WD, the front and rear axles cannot rotate at different speeds, as the transfer case does not contain a differential. An engageable 4WD vehicle can operate in 2WD, 4WD high range, and 4WD low range.

Permanent 4WD systems drive all four wheels continuously.
A differential in the transfer case allows the driver to remain in 4WD regardless of the surface. This differential prevents transmission stress by allowing the front and rear axles to rotate at different speeds. In turns, it enables the inside wheel to slow down and the outside wheel to accelerate. Many permanent 4x4 vehicles feature a central differential lock, operated either by an electronic traction control system or manually. A permanent 4WD vehicle can operate in 4WD high range and 4WD low range.

Engaging 4WD is done via the transfer case, which distributes power from the driveshaft to the front and rear axles. With older vehicles, it is sometimes necessary to come to a complete stop and put the vehicle in neutral or park, then manually shift into 4WD using a gear lever. In modern vehicles, 4WD can be activated simply by pressing a button. There are several types of 4WD systems, each with slight differences in operation. Check your owner’s manual to ensure you are using your 4WD system correctly.

Like vehicles with permanent 4WD systems, AWD vehicles use a central differential to distribute power to all four wheels. However, most of these vehicles do not have a transfer case, which locks power distribution equally between the front and rear. As a result, they usually operate as front-wheel drive, sending torque to the rear wheels only when needed. Automatic sensors detect wheel slip and apply torque to the wheels with traction.

The AWD system is mainly designed for on-road use. These vehicles can handle light off-road conditions but do not have the capabilities of true 4WD.

Many modern vehicles are equipped with some form of traction control. Traction control helps keep the vehicle moving by instructing the computer to apply braking if necessary to prevent the wheels from slipping and losing traction. It can be activated via a simple on/off button or may have multiple settings. Check your owner’s manual to understand all its functions.