These links take you to Info about transmissions on diesels but you'll see pictures of the vacuum modulator and related information.

http://www.continentalimports.com/ser_ic20242.html

http://www.mercedesdismantlers.com/722.3and722.416_transmission_adjustments#722.3%20Series%20and%20722.416%20Transmission%20Adjustments

You can also search the forum for *vacuum modulator* for more Info.