If the answers to my questions above are "yes"... That gear is supposed to move freely. When moved to the driver's side, the rear diff is unlocked. When moved to the passenger side, the rear diff is locked.
If you have taken the whole actuator apart, the armature may move or the actuator gears may move. In either case, there is no guarantee that the actuator gear is properly aligned with the diff gear any longer, when you install the actuator again. There is a write-up on the web if you search, which helps get the actuator back in sync with the diff gear. You should search for it. I believe it goes something like this...
-Plug the actuator in and put the actuator in the unlocked position.
-With a screwdriver, move the diff gear all the way to the driver's side.
-Then, install the actuator.
I think that is the only way to make sure it is lined up. Putting things together with the actuator in an unknown position, or putting it together with the gear and the actuator in the locked position will lead to problems.
