I have a similar noise on my 88 300ce. My indie said it could be a spindle; I haven't had it fixed yet so I don't know where or what that part is. Hope this helps.

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87 300e (white/black; amg body kit)
88 300ce (red/cream; amg body kit)
93 300ce cabrio (white/blue/blue top)
93 300ce cabrio (black/grey/black top)
98 ml 320 (totaled @ 137,000 miles)
99 clk320 (black/grey/black top)