The car: 84 300D, ~210,000 miles, brown , runs good, but transmission won't pull in 3rd so never gets to 4th. (See this thread: 84 300D Transmission Woes ).
Me: cheap, know little about benz's, less about diesels, nothing about transmissions.

So I looked at the DIY page about transmission vacuum control tuning (http://www.peachparts.com/Wikka/TransVacTune). The first test recommends testing vacuum coming out of the pump. To test it, I pulled the line that behind the engine block out of the first wye connector past the green damper thingy. Using my Mity Vac, I got 14 inches at idle, that dropped to about 9 at around 2000 RPM, and didn't decrease at 3000 RPM, which was all I could get my assistant/wife to rev it to ("somethings burning!" "It'll blow up!").

I figured that was reasonable, since 3000 RPM is about what it revs going 65-ish, so maybe that's enough. The DIY page says that vacuum should drop to zero at full throttle, and it did drop near zero during the hard accelerations. So, after all that preamble, my question. Is that pretty much what I should expect, or does my pump suck too much?

TIY for any and all advice, comments.