Almost certainly front flex disk. I have the same problem, just haven't got around to fixing it yet.

Do you have any "clunks" as it downshifts at slower speeds?

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2016 Monsoon Gray Audi Allroad - 21k
2008 Black Mercedes E350 4Matic Sport - 131k
2014 Jeep Wranger Unlimited Sahara - 62k
2003 Gray Mercedes ML350 - 122k