I have heard a rattle in the rear of my 83 300D for some time, expecially when going slow over choppy roads or bumps. I had the tires off the other day, and saw that the rubber around where the bolts attached the plastic links to the hub and sway bar were gone for the most part...

Had my car in for alignment and had them install the links as well... Such an improvement!!! Here I was worried because I would yank on the driveshaft and halfshafts and couldnt get much play, yet heard a rattle... I thought a tooth in my differential snapped or something.

So check those white plastic sway bar links on the rear bar... they can fix the rattle when the old rubber falls out and they are replaced.

JMH

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Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1985 190D (169k)
1991 350SD (116k)
1991 350SD (206k)
1991 300D (228k)
2008 ML320 CDI (199k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (267k)

Past Diesels:
1983 300D (228K), 1985 300D (233K), 1993 300D 2.5T (338k), 1993 300SD (291k)