Does anyone know if there is a way to test or tell if the green colored dash pot valve is defective or not?

As far as I have been able to tell, it is just an oriffce, a hole in a can...no moving parts...it just restricts/reduces/meters vacuum. If you can blow through it and it is still in one piece with no cracks, it should be fine. Or clean it out with a straight pin, small wire, or tiny drill bit...being careful not to enlarge the "hole".

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Mark
1983 300TD Wagon
Even a broken watch is right twice a day

If you are talking about the check valve on the vacuum system, you should be able to suck air from the side that has a hose going into the engine compartment, and you should be able to suck and air through the other side. If you can suck through air through both sides it needs to be replaced.

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my problem is erratic shifting. you can push down on the accelerator lots and it won't build up big speed because it will continue to upshift. Then on a the other side it will stay in a gear and stay there way to long. No consistency in the shifting pattern. Has anyone encountered this problem, and some possible answers to where to look. Thanks

Maybe try adjusting your bowden cable. It is involved in the time of shift. Try searching the forum for exactly how to adjust it. It's easy. It is a cable on the top rear of the valve cover, that you can adjust by hand.

You may also need to start troubleshooting the vac system. There are lots of places it can leak.

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My understanding is that the vacuum helps dampen the shifts. As far as I know, it has nothing to do with the timing of the shifts. If I were you I would use the search function to look for other possible problems. The Bowden cable that was mentioned might be one thing to think about. I would guess that the kickdown switch might have some problems, too, if you're pushing the pedal down and it just continues to upshift. When you push the pedal down it's supposed to downshift.

If I'm wrong about the vacuum and what it does others will hopefully chime in, but I think it's probably not your issue.

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Ralph

1985 300D Turbo, CA model
248,650 miles and counting...

For $4.40 to replace it why worry? Just buy a new one if you are concerned.

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Rusty Cullens
BuyMBparts, Inc.
1-800-741-5252

If sometimes you have early shifts and sometimes the shifts are difficult, it sounds like a sporadic leak in the trans vacuum.
The green vacuum dashpot on top of the VCV is not a check valve, but a dampening orifice, and should have a restricted flow from either side.