The Select Drive System vacuum controls consist of a mode selector mounted on the instrument panel, a vacuum storage tank, two vacuum operated shift motors, two check valves, and all of the necessary connecting tubes, hoses, harnesses and mounting brackets.
The vacuum shift motors are not interchangeable. The axle shift
motor is vented but the transfer case shift motor is not. The axle shift motor is vented
to prevent lubricant from being drawn out of the axle by vacuum if the shift motor seals
become worn or damaged.
Click for a vacum hose routing diagram
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