You have the manual vss, early production. The later one is all electronic. yes the top piece turns when you turn the bottom and is not part of your cable. The cable has the screw on nut that screws to the top of the vss and a small protrusion that pushes down into the slot in the vss and then you tighten the nut. Maybe you have a peice of the protrusion stuck in the bottom preventing you from pushing it in and secureing the nut. You may have to replace the vss if you can't get it out.
