Support the transfer case crossmember with a hydraulic floor jack, then loosen and remove the six bolts that hold the crossmember to the frame. Carefully lower the entire assembly about 2 inches. Place the Rancho spacers between the frame and the crossmember with the conical end toward the crossmember. Put a conical washer on each bolt, use a threadlocker, and then thread it into the frame. Tighten the six bolts to 30 lb-ft.