2002 OBW, 5-spd, 35,000 mi:
When I operate the car between 40-45 mph, the car vibrates noticeably (must be, the wife notices it too!). Also notice every deep crack in the road or bump sounds "louder" than it used too when you drive over it. The vibration is audible and is even more prevalent in 4th gear at this speed, possibly the vibration matches the normal vibration from the motor at this rpm? just a guess.
Tire pressures are all equal.
Would anyone suspect alignment and/or balancing issues...or anything to do with the AWD system?