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Old 10-12-2006, 01:21 AM
Samuel M. Ross Samuel M. Ross is offline
Join Date: Dec 2005
Location: CA... No. of S.F.
Posts: 890
Here is some more info for you to mull over...

Originally Posted by phillipb View Post
With vacumn on spec with old modulator it would shift 1-2 VERY quick then 3 and 4 all too soon. Removing vacumn helped some but 1st shift was very hard. Put in new modulator Hard shift to 2 (bark tires) then not shift to 3rd at all. Have tried some adjustment to modulator but no help. If I disconect vacumn , nothing changes.
Thank You
Since you say your MBZ is an '81 300CD, this means it is a W123 chassis and has a 617.912 engine... which means this should be the vacuum diagram for your engine/tranny shift control system:

I think you will find your modulator adjusts over a range of ~100 "clicks" [ 8"clicks" = one 360 deg. turn] or ~12 turns. If I were you I would first make certain that the various OTHER components of your vacuum syste are functioning and that you repair any leaks... and then put your modulator at about mid-range of its adjustable range.

Q1 - Have you read the Steve Brotherton article? If not check it out at:
Q2 - Do you need a combo vacuum hand pump & gauge? You'll need one.

Now we anxiously await your questions and IF you don't have several to many, then we probably will not be able to talk you through this! Seriously, it's a bit abstact but certainly doable !!
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