1984 380sl is this normal

Nope not normal but should be easy fix.

1. Clunk means loose vacuum hose on the tranny... One the driver side of the tranny... by a round device there is a vacuum hose... most of the time, the hose deteriorated and is very loose. Change it with MB vacuum hose 1.5" length. but get a foot for spare.

If the vacuum hose is tight, then you have to adjust the modulator... BUT higher engine idle RPM can do the same clunk.

1. Engine should idle at 800 when not in gear. In a gear, it should idle at

500-600. If not, then it is most likely the idle control unit that is bad... get it from Automotive Technical Service... look for the info at mbcoupes.com under part supplier.

There is a procedure to test the entire circuit with a multimeter... measuring voltage and resistance to determine which one is at fault before you replace it... you can get that info in a MB service manual CD.

You adjust the modulator AFTER you've adjusted the switcover valve on the IP and you only fo that AFTER you've verified the vacuum itself is to spec.

Just jumping in here. I hope this thread stays alive a little longer. I am just starting to look into this problem and have found the modulator valve on the right side of the transmission. I have had no luck with the vacuum line locations so far. The articles in the above web site are great and I will re-read them as to the vacuum lines. Thanks for the great link. wolf1

You can look up all the old threads on google.com whereas direct newsgroup link only holds 3 days.