Ok if you want to work on it now, more power to you.

You need to first check that you are getting normal output from your vacuum pump and that all of the fittings (rubber y-joints, etc) associated with your vacuum hoses are still sealing tight and not dry-rotted and potentially leaking.

To start, disconnect the main vacuum line at the brake booster inlet and use a mityvac or vacuum gauge to check output. It should be 19-22 Hg. If that is okay, you can move on with diagnosis/adjustment. If it measures under that, your vacuum pump needs attention before you do anything else.

Here is the main thread for transmission vacuum issues:
It's CRITICAL... how you set your transmission's vacuum system on your diesel MBZ...

You should also read this very extensive collection of transmission info:
DIY W123 Transmission Diagnose and Adjustment 722.xx OM 616-7 - Benzworld.org - Mercedes-Benz Discussion Forum

Edit: I just went back and reread your original post and noticed your reference to other vacuum issues. You really need to make sure you don't have a vacuum pump issue or vacuum leak, before you do anything else.

This may be helpful:
Mercedes Vacuum Troubleshooting

Good luck with it.

__________________


Mac
2002 e320 4matic estate│1985 300d│1980 300td
Previous: 1979 & 1982 & 1983 300sd │ 1982 240d

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