[sanddrag]

The output shaft does not move axially/linearly. There is a hole drilled in the back end of it, and a "shifting rod" inside it which connects the pneumatic cylinder to the shifting dog. Just like any other dog shifting transmission I've ever seen (andymark, etc)

The "red thing" is a pillow block that carries the outer bearing for the output shaft. It does not move. The wheel is driven by the hex milled in the end of the output shaft. Not shown is the frame rail to which the gearbox face mounts. The frame "red thing" goes through the frame rail. Tha flange sits on the outside, and the face of the gearbox sits smack up against the other side of the frame rail. Very clean.

EDIT: Travis beat me to it. But yes, what he said ^^