I'm going through this right now myself. The one I'm working on has a problem with the valve on the IP I think, so I'm way off from where you are. It sounds like yours is much closer to being right.

I don't totally understand why there are two. One of them has a telescoping effect, maybe a damper inside.

I think you will find it helpful in understanding how this contraption works if you take off the black plastic cover on top of the valve cover.

To further understand what's happening, vacuum is supplied through an orifice at the vac booster line. As the throttle is moved, the vacuum switches underneath the black plastic cover bleed off the vacuum to decrease the vacuum as the throttle is pressed. This is supposed to simulate the vacuum of a gas engine.

Tee a vacuum gauge into the line that goes to the transmission. It should vary from about 15 or 20 at idle to between zero and two at full throttle.

Do a search and find my thread entitled "'81 300D Modulator" or something like that. There are two links in that thread that will provide extremely useful articles for you.

Good luck,