I took my 2006 Dodge Ram 3500 to the dealer last week to have them check out a safety recall related to the steering linkage. They informed me that no action was necessary...fine. However, now I have a very noticeable vibration that I didn't have when I dropped the truck off. Most noticeable between about 53 and 59 MPH. Definitely a speed vs. engine RPM issue. I suspect a rear driveshaft issue (balance or U-joint?), but my question is, what could they have done that would cause it since they were only (supposedly) checking the front end? Again, my issue is that it wasn't there when I dropped it off. I haven't found anything obvious. Also took it to a different shop for a wheel rotation and balance just to make sure that wasn't it. Still experiencing the vibration.