Load Level Diagnostic - What to ask
 

okay so things are getting weird. Here is the story.

The load leveling on my 95 E320 wagon with 120K used to work fine. then the pods went out. I put in new pods. during that install I stripped the threads on the valve body. I got a used valve body. everything is put back together. no load leveling function. there are no leaks as far as I can see, and oil level hasn't gone down a millimeter. the wagon remained at normal height though. when I would load it up with 300-400lbs, it of course would sag down and not lift. when I unloaded everything, it would return to normal height. Over time (weeks) car now sags all the time. not totally bottomed out, but significantly drooped. Also, I attempted to test the valve body. car was running and back of car was on ramps. I disconnected little arm and moved the valve body lever manually. no motion in any direction.

so thats where I'm at. Not sure where to go now. I was planning on taking it into a good shop here and want to ask them to look at it. knowing the above information, what do you think I should ask them to look for? off the top of my head, I would want to know:
1) pressure of line coming into valve body (to see if pump is providing enough pressure)
2) pressure of valve body output line (to see if its the valve body)

I would assume everything needs to be tested under load (weight)

I'm just kinda lost at this point. :(

You've got the basics right. Either the pump is not supplying pressure, or the valve is not passing it on the the "legs." Between the two, I would think the pump is the more likely failure.

All this based on rather limited experience with my S500 Coupe, which has basically the same setup.

Did you bleed the air out of the system? Crack the various lines while the engine is running and see if anything comes out.