Mercedes: transmission, vacuum modulator, shift points

Question
83 td, automatic transmission, engine runs fine, i have reverse with no problems, in drive the vehicle doesn't seem to get enough rmps to shift gears, when this first happened i could change gears manually, now that doesn't seem to help.turo seems fine, i am thinking this is vaccuum leak?

Answer
Tom,
I believe that you may be on the right track. This transmission may a vacuum modulator in concert with the governor to control shift points. A vehicle of this age has some very brittle vacuum hoses. The can develop stress crack that are very difficult to see. A vacuum check is the best way to fine out.
Good Luck
Rob