I have an '82 240D automatic and am working on the rough-shift issue myself.
First thing to look at is whether the vacuum lines are correct (mine aren't).
Print this out:
http://home.comcast.net/~phantoms/vacuum/fuel_egr_240d_auto.jpg
And go look at your car and see whether that's how things look.
If not, step 1 is to restore the lines to how they should be. It's possible that as the car's aged it now needs a different color orifice than it has. You can get them at Benz dealers.
You may wish to read this thread (it's long) on this topic, and in particular the linked article by Steve Brotherton.