A system that mechanically forces the front and rear axles of a four-wheel drive vehicle to rotate at the same speed. This creates a true, locked four-wheel drive engagement, maximizing traction in challenging off-road conditions. For example, when one wheel loses traction on a slippery surface, power is not diverted to that wheel, but instead remains evenly distributed to all four wheels, enabling consistent forward movement.
This feature provides a significant advantage in situations where maximum grip is essential, such as navigating deep mud, snow, sand, or rocky terrain. Historically, it was a common feature in early four-wheel drive vehicles, designed to overcome limitations in differential design and ensure reliable propulsion in demanding environments. Its utility lies in its ability to bypass the differential’s function of allowing wheels to spin at different speeds, forcing them to rotate together.
