I've noticed that the vibration only occurs when there is a load on the engine at idle, by placing it in drive or reverse with the brake on, and when that happens the rpms drop about 75 from 780 to about 705, and occasionally into the 650-700 area when the AC unit clutch activates, and the vibration gets much worse.

Are the rpms supposed to drop that much when the engine is engaged/loaded by the transmission?

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Mark
2001 3.0 Original Owner, still going
2012 E70 xDrive 35i Pre-Owned -- sold because no one could figure out the transmission problem