Just a thought though.

When you have your driving wheels off the ground, the drive line is unloaded for all practical purposes. This would change the behaviour of the system (for vibrations) compared to a loaded system like when you have the wheels on the gound and the vehicle is being driven.

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1986 300E (3/2002) Rear ended and totaled (10/2009)
2000 Xterra (5/2000)
1992 400E (11/2009) -Sold
1986 300E (12/2009) - Sold
2004 E500 Wagon (6/2013) - Sold