x2 on the vacuum pump. I had a similar sound in my 1985 300D. Forgot how I decided it was the pump, probably using my HF stethoscope (i.e. screwdriver to ear). The pump arm had worn half thru in 150 mi of driving since my son first heard it. A bit more and the parts would have slid into the timing chain w/ disastrous results (happened to a poster here a few weeks ago). I found most of the little balls from the failed bearing in the oil pan.

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1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans