RZ67 Tilt-Shift Adapter: Did I just get stuck with a broken one?

I bought a Mamiya RZ67 Tilt-Shift Adapter off ebay and I paid reasonable for buying one in full working order. It just arrived and I think it's missing an important piece. The tilt movement works as you'd expect: loosen locking knob, turn tilt knob, and the thing tilts up and down. However, the shift movement doesn't behaving the same way. Loosen the locking knob and it falls to the bottom of its travel. Turn the shift adjustment knob and nothing happens. At first, I thought maybe the shift adjusting knob worked as a stop and not as a positive control but you can't turn the shift adjusting knob far enough to touch anything that might let it function as a stop. The tip of the shift adjusting knob is ball shaped like it's the male half of a ball and socket joint (makes sense since it has to work even with tilt applied) but there's no female part for it to fit into.

How is the shift actually supposed to work? Is this TS Adapter missing something?

I'm not familiar with that adapter, but have you checked the manual? http://www.cameramanuals.org/mamiya_pdf/mamiya_rz_tilt-shift.pdf

The manual was the first place I went. It doesn't show a clear close-up of the back side where the shift adjuster is. I couldn't find a clear picture of that area on the internet either.

Took me a while to get pictures but looking at it closely, it really looks like it's missing a piece. It looks like there was some sort of an extension/pusher that fit up into the housing for the shift adjustment screw and pressed down against the small black bracket with the 3 tiny screws in it. You can see a dab of grease up inside the shift adjustment screw housing as though there was something sliding there in the past. Can anyone confirm?

Bump.

Old thread, but I didn't see anyone answer it.

Yes, a piece is missing. The knob adjuster is a screw drive, and the missing piece attaches to the lens plate, and has a slot for the screw drive to adjust the plate up or down. I cannot see into the housing on my T/S adapter, but can surmise how it works.

Stuart