Another transmission question
 

I have an 83 300 turbo, under normal driving conditions it tends to shift thru all the gears rather quickly. The first shift comes along around 10-15 mph and the other two are almost immediately after.Yesterday I was checking under the hood and found a vaccum line off at a Y connection near the brake booster. I didn't really take the time to trace it and see where it went,the general direction was towards the rear of the engine and toward the trans tunnel. I read something on here a while back about some people having similar issues. I need to check the rest of the line and replace/repair as needed.The shifting improved after connecting the loose line,if I find no other sources of vaccum loss, is the vaccum modulator adjustable? I am assuming it has a modulator as I have not had time to get under it yet,I know that some modulators had a screw in the hole that could be adjusted to change the shift points.

http://www.continentalimports.com/ser_ic20242.html TRANSMISSION VACUUM ADJUSTMENT

WIKI Transmission adjustment
http://www.peachparts.com/Wikka/TransVacTune

Transmission adjustment Thread
http://www.peachparts.com/shopforum/diesel-discussion/158216-its-critical-how-you-set-your-transmissions-vacuum-system-your-diesel-mbz.html

Adjusting the Transmission Modulator
http://www.mercedesforum.com/forum/showthread.php?t=39889

The MB Transmission relies on the vac to determine the quality of the shifts. Some types also use the vac to determine the shift-points I think--those models without a cable from accel. linkage to transmission.

--Those with a cable use the position of the cable to determine the shift-points and not the vac to the trans....

Its important to make sure ALL the vacuum system including the VCV on the side of the IP is working correctly and set up right BEFORE any alterations are made to the transmission Modulator-valve at the side of the transmission case...

--If you alter this before getting the vac system Right, then you'll be making much more work for yourself and could actually 'mask' the real faults...

There are a number of 'Orifices' in the various vac lines of the M.B. and these can and do block from time to time....
--This can give a variety of faults....