You may want to check the "harmonic balancer" thread in Tech Help...it's the sticky post at the top of the thread list.

If your problem is indeed caused by the offending part, a failure would do some real expensive damage...

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2009 ML350 (106K) - Family vehicle
2001 CLK430 Cabriolet (80K) - Wife's car
2005 BMW 645CI (138K) - My daily driver
2016 Mustang (32K) - Daughter's car