A vibration felt through the center floor of the vehicle can be caused by driveshaft flex discs, which crack and shred, causing excessive driveshaft movement. Not repairing these can cause damage to the driveshaft center support bearing, or, in the worst case scenario, damage to the transmission or differential.Google+
Car Problem Reports
Mercedes-Benz E350 4MATIC Cracked Driveshaft Flex Discs May Cause Driveshaft Movement/Vibration
Mercedes-Benz E350 4MATIC Problem
Average Mileage: 104,000 mi (90,000 mi - 112,000 mi)
Visitor, 2006 Mercedes-Benz E350 4MATIC, 112,000 mi
Felt vibration during driving. Shortly afterwards, drive shaft snapped.
Damamge to rack and pinion too