I have a 82' 240D that stopped shifting well. It Shifted into 1,2,3 but not fourth and all were delayed to the last rpm possible before the redline. I Bought a new Vacuum modulator, and it made all of the difference, and none of the difference. it now starts out in 2nd and shifts to 3rd and 4th very prematurely. The adjustment key made absolutely no difference whatsoever. it turns out that the vaccum modulator I pulled ot of the car was exactly the same EXCEPT that in the one I pulled out there is a short (1-1/2 inches) metal rod with a spring snugly around it sticking out of the hole on the side that goes into the tranny. And it does not appear to be removeable. I thought I got the wrong modulator, but all the part pictures of the VM online for my model of car look exactly like what I just bought. No rod/ Spring. What the heck is going on here? Has anyone had the same problem? It seems as if the modualtor I need doesnt exist.

The rod and spring must be transfered from the old modulator to the new one. Unfortunately, I'll wager that your problem is lack of vacuum rather than bad modulator and once the new one is working properly it will work like the old one.

You might try looking at this article if you continue to have problems after the rod and spring are restored: http://www.continentalimports.com/ser_ic20242.html

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

As you noted, the rod/spring assembly did come out after a encounter with a pair of vice grips (it appeared to be glued into the old modulator and took some force to remove). When I replaced it, it was as you said, exactly the same as the old one- incredibly hard and late shifts into 2,3 and no fourth. It actually shifts so hard (and has so much RPM momentum) that the tires "bark" when you go from 1st to 2nd. I have started to look at the article and it looks very juicy to me, having no other clue as to how to find out what is going on With my tranny. I want this tunnel of transmission issues to end. I should also mention that the flippers that close the vaccum valves on the top of the valve cover assembly, are fine (a past problem) and the fluid and filter are both fresh, and the fluid that came out looked fine (as it should). There is also no apperent total vaccum faliure, as the brakes and door locks and fuel shutoff are all working. The only thing that is out of whack is that the drivers side door lock has to be locked to shut off the car, and it has been like that for many years. If you have any other clues other than what is give in the article, I'd love to hear them, as I know no other way of finding out what is going on.
Thank You,
Justin O'Dea Bozeman, MT

Do you have a "Hg vacuum gauge you can tee into the line going to the tranny? The signal to the tranny should be close to full vacuum pressure at idle and go towards 0"Hg as you press the throttle to the floor. There is a controller on the upper rear part of the IP that generates this curve. It sounds to me like you don't have any vacuum on the line.

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Jim