Analysis of Vibration
WARNING: This page is about a different car, the 2007 Mercury Mariner and 2007 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.
Few vibration conditions are caused by the RDU. For a vibration concern, follow the diagnosis procedure in NOISE, VIBRATION AND HARSHNESS article unless there is a good reason to suspect the RDU.