Plumbing Problem

I have a Bathtub Shower combination with the H and C control over the tub and a Push Pull "Diverter only" on the wall between the shower and the control. This Push Pull device leaks through the control tod.

I screwed the Knob off, then the sleeve the rod comes through. I then took off the decorative tube that goes over the sleeve.

My problem is, I cannot get the rod and valve out of the portion of this control that actually controls the water flow. The rod still pulls out "Under spring tension" as it normally does, but I cannot get the entire valve out. It is inside another tube, and I cannot get ahold of, or see anything like a nut to work with.

How do I get it out.

There are no visable manufacture marks except on the tub overflow cap.
it is WATCO.

Thanks in advance for any help.

Bert

If you post a pic of the unit, someone will be able to tell you what model it is and how to pull it out