There appears to be to much "coupling" between the engine and transmission at idle unless I'm in Park or Neurtal. The effect is a fair amount of vibration and shutter. Is there an adjustment that reduces the "coupling" at idle speeds? Idle speed in gear is about 500
RPM and out of gear about 750.

My 300SEL does this as well...I thought this was normal?

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Current cars:
2000 ML55 AMG, 174k miles
2003 C240 T-Modell, 202k miles
1995 S320, 207k Miles