What adjustments are to be had on the transmission modulator valve (on tranny), and how are they performed?

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RIP: 80 300SD
RIP: 79 450SEL
2002 E430 4matic (212,000km)
2002 ML500 'sport'

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FACEBOOK: PANZER450

Silly question.

if my modulator is leaking can't I dip it in something that'll coat the outside and seal it up completely? or would a leaking modulator be an internal thing. I'm talking about the vaccum element on the transmission.

__________________
RIP: 80 300SD
RIP: 79 450SEL
2002 E430 4matic (212,000km)
2002 ML500 'sport'

____________________________
FACEBOOK: PANZER450

Leaks are typically internal caused by a ruptured diaphragm. You can seal the outside but that won't get the modulator to work properly or keep ATF out of your vacuum pump.

Sixto
93 300SD 3.0

Sam has very good information posted about the transmission control systems including all the proper vacuum checks in the archives. I believe one should own and use a mityvac type tester to establish all is well with the vacumm prior to adjusting the modulator valve to compensate for probable vacuum problems. Or a cetain amount of transmission wear. If the modulator valve will not hold pressure with a test it should be tossed. These transmissions are also tuneable to a certain extent and that is a good thing. It was quite an effort for Sam to research, question and evaluate all he did. You get the results and usage of it for nothing. All you have to do is step up to the plate. This type of thing makes this site invaluable. It also increases your knowledge beyond what the average guy knows about transmissions. This is just my spin and beliefs on the subject.

Get a mity vac and pull vac on the trans. modulator. It won't hold vac but it should hold it for a little bit. If you pump you mity vac and the needle won't go up past a few inches of vac the modulator is shot. It should take a couple of pumps to get some vac on the modulator then the needle should take some time to drop back to zero. I usually pump mine up to about 15" and then it should take about 30sec or so for the needle to drop back to 0".

You can adjust the modulator if it's not leaking vac. If you pull the rubber cap of the modulator there is a t-handle key underneath that you pull out part way and turn. Only turn it a notch or two at a time. I don't remember which way firms up shifts and which way softens shifts. Search the forum a bit and you should find it.

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Try here for adjustments:http://articles.mbz.org/transmission/adjust/
Or if it's a vacuum leak more than likely it is this little cap:http://catalog.eautopartscatalog.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=catalog.mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=1ZO0QOK8B2030PE9AT&year=1984&make=MB&model=300-SD-002&category=J&part=AT+Modulator+Cap
If the leak is more extensive, then I would replace it. However, try the other things first because there is more to it than slapping a new one in place.

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Sam

84 300SD 350K+ miles ( Blue Belle )

a little more to it? like what?

__________________
RIP: 80 300SD
RIP: 79 450SEL
2002 E430 4matic (212,000km)
2002 ML500 'sport'

____________________________
FACEBOOK: PANZER450

Steps 12 on, in the first link I gave you........................

__________________
Sam

84 300SD 350K+ miles ( Blue Belle )