I am trying to track down a shifting problem on my 83, 240D. I have used the search function but come up with some conflicting info. The shifting is very soft going from second to third and third to fourth when under slight acceleration. Shifting if firmer under heavy acceleration. I have measured the vacuum at the line going to the transmission module. At idle speed the vacuum gauge reads about 16" - at full throttle it drops to about 5". I have read that it should drop to zero. I have also read that it should drop to about 5".

Questions:

1) Which is right zero or 5 inches at full throttle?
2) Do I have a bad vacuum control valve (VCV)?
3) Is there any adjustment that can be made to the VCV?
4) Is there a "vacuum bleed" line that could be blocked?

So many questions, so little time

This forum is the greatest. It has saved me much time and money.

Thanks for your help.

Bill

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Current Vehicles:
1990 Mercedes 300SE (147,000)
1985 Mercedes 300SD (203,000)
1983 Mercedes 240D (167,000)