Rough shift??? Check this.
 

In preparation for the month long trip to AZ, I changed the oil & filter on the 560. While the oil was draining I did a pretty thourough check of everything I could while the car was on ramps.

The car has always had a bit of a stout shift, not banging hard, but stout. I decided I would attempt a little vacuum modulator adjustment.

While trying to work off the rubber cap of the modulator, I accidently bumped the vacuum line. With the slightest touch, the line separated from the connector. Close inspection of the rubber connector found it intact but very hard. I replaced the rubber connector and finished changing oil.

Once finished, I went for a short ride, shifts much smoother. Came home and opted to adjust the modulator only one notch counter clockwise. Test drive showed shifts were even smoother.

Moral of the story - check that little rubber connector at the modulator before making any adjustment. Replace if cracked, worn or cooked hard as bakelite. Shoot, in hindsight, I'd say replace it on GP if you're in the area.

Mike - It is amazing how such little things on these cars can make such big improvements. I think we are all in too much of a hurry to rush into the heavy $$$$ repairs.

Thanks, I will keep this one in mind. Matter of fact, I should check the '91 300E when the rain stops.

Haasman

Thanks for the information, Mike!
 

I will check this since mine tranny do shift hard sometimes, sometimes not. This could be caused by a leak, right? Especially in areas with shifting climates?

Thanks for sharing this with us!

Great report. Thanks. Last time I was under there mine was also as hard as a rock. I thought that was normal:rolleyes:
It may be the source of my vacumn leak.

Question: Did you buy the replacement from MB or was it a generic part from a hardware store or the like?

MB part??? No way.

I just used about a 3 inch section of standard vacuum line, the small stuff for a nice tight fit at the hard plastic line. 3 Inches allowed me to get the hard line in pretty far so I wont have to worry about it getting bumped out of position.

Noticed today I could only barely feel the 2nd to 3rd shift and most of the time I could only tell the 3rd to 4th shift by the tach. Very sweet.