Is your car a 4Matic? They have already replaced the transfer case on my 2004 4Matic for noise with under 10K miles...maybe that is the same problem. Take it up with MBUSA and have a zone rep meet you at the dealership to test drive it - that should get them moving on fixing it.

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz