How to Make Your Car Last Forever: Avoid Expensive Repairs, Improve Fuel Economy, Understand Your Warranty, Save Money

and rear wheels. The center differential allows the front and rear wheels to turn
at different speeds as needed, letting the full-time 4WD work automatically. Very
simply, when engaged in automatic 4WD on a dry straight road, the system
operates in two-wheel drive. When the wheels start to spin due to slippery road
conditions, the system reacts to wheel-spin by progressively locking the front
and rear wheels together to optimize traction. This system is limited because it
requires the driver to determine when to engage it.