I'll check things out this weekend when I pull the car off the road. Based on what I described, any ideas on what it MIGHT be? I looked at the stack of receipts that came with the car and it looks like the both flex disks were replaced by the previous owner about 40 - 45K ago. No mention of U-joints or driveshaft bearing.

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2012 Mercedes ML350 Bluetec 102K (hers)
2005 Corvette 55K (fun car)
2002 VW Jetta TDI 238K (mine)
1998 Volvo S70 T5 Turbo 211K (kids)
1994 Ford F150 4WD 246K (firewood hauler)
1983 Mercedes 300D 384K (diesel commuter)