This vacuum actuator by Autoround, with part number 600-105, is a 4WD locking hub that fits Expedition Navigator NOS. It includes mounting hardware and lubricant, and is compatible with several superseded part numbers such as 7L143C247AD, 7L143C247AC, and 7L143C247AB. The actuator is designed for left, front, and right placement on the vehicle and has an interchange part number of 1S12254. It has a gear ratio of 3:73 and is made in China. This item is not a vintage part, and although it is not a universal fitment, it is a perfect fit for Expedition Navigator NOS. 4WD models ONLY.