Q. Why don't I see anything happen in the viewer when I z-translate an object?

A. z-translating an object moves the object closer to and farther from the camera eye. With a parallel projection, the object looks identical whether it is nearer or further away from the camera.

You must turn perspective viewing projection on to see a change in the object when you z-translate it. Using perspective viewing projection, the object gets smaller as it moves further away from the camera and it gets larger as it moves closer, so you will see a change when you z-translate the object.