Do what Peter said first, because it's the most like cause. But don't forget about the U-joint. I went through this on a 300E and it turned out there was a detent worn in the U-joint. IF that's the case, the tech might tell you that the whole driveshaft has to be replaced and even show you how the U-joint is straked in there so that it can't be replaced. That's what happend to me and the used driveshaft he put in was barely better than the original. However, there are companies out there that can replace the U-joint with a brand new greasable one. Spendy, but not as much as a new shaft.

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Rick Miley
2014 Tesla Model S
2018 Tesla Model 3
2017 Nissan LEAF
Former MB: 99 E300, 86 190E 2.3, 87 300E, 80 240D, 82 204D Euro
Chain Elongation References