Here, the fork is currently in "disengaged" position. It tended to stick in this position, so I decided to force it into engaged position permenantly. I popped the e-clips off of either side of the fork and off the insert which mounts the vacuum motor. Slide the vacuum motor and shaft out. Cut a small pipe (I actually used a piece of an alternator spacer tube) to size, assemble it on the shaft BEFORE the fork, and then slide the fork on, and click the bigger e-clip back on (you won't need the two e-clips around the fork anymore).

My main reason for doing this was that I swapped drivetrains and no longer had the vacuum switch in my transfer case. For a while I simply ran manifold vacuum through a check valve to one side of the vacuum motor. This lasted a few months and then something failed (I didn't care to investigate). Now I won't have to worry about it.