You can't guess at what hte vacuum and modulator are doing unless you don't want to fix it. Professor Google has lots of information on the various 722 iterations.

Here are a couple of links.

http://www.transtec.com/downloads/tech_inserts/mercedes/94642.pdf

http://www.transtec.com/downloads/tech_inserts/mercedes/94642.pdf

Mercedes-Benz Transmission, Steve Brotherton, ImportCar, February 2002

Adjusting the trans without going through the testing process is akin to urinating off the high side of a sailboat.

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85SD 240K & stopped counting painted, putting bac together. 84SD 180,000. sold to a neighbor and member here but I forget his handle. The 84 is much improved from when I had it. 85TD beginning to repair to DD status. Lots of stuff to do.