Unique drivetrain With the full-time 4WD, however, the center differential absorbs such differences, ensuring smooth and reliable cornering. Previously, center differentials took up too much space in the chassis layout, added much to the weight, absorbed interior accommodation and interfered with driveability. Featuring a new planetary gear system, however, the differential of the 323 4WD is more compact and lighter. Furthermore, Mazda has located the center differential on the same axle as the front differential which saves space, giving more passenger and cargo room. The torque distribution is set at 50:50 to cover use on any type of road surface. Differential lock-up mechanism Even when a wheel has momentarily lost traction, and would otherwise immobilize the car, the 323 4WD's electric lock-up mechanism, built into the center differential, will instantly allocate the torque to the remaining wheels, thus eliminating such a problem. The lock-up button is located on the instrument panel in easy reach, with an adjacent illuminated indicator showing whether the lock-up mechanism is on or off The secret is a compact planetary gear system The secret of the full-time sure-footed performance of the Mazda 323 4WD lies in it compact center differential mechanism. It is the mechanism that separates the full-time 4WD from the conventional part-time. In a part-time 4WD, where the front and rear wheels are directly connected, the difference in rotation between them brakes the car in tight cornering, unless the 4WD is disengaged to make it a 2WD.