Don 
2001 Toyota Avalon Sedan XLS 4dr Sedan w/Bucket Seats (3.0L 6cyl 4A)
Wind Humming
 I purchased this vehicle from a private owner with 19000 miles on it.  The only problem I experienced in the 4 years I have had the vehicle was the windshield.  I noticed a humming sound coming from the windshield especially when driving at highway speeds in a cross wind.  I took it to the dealer and was told that was normal.  I insisted there was something wrong and asked to talk to the service manager.  After speaking to him he contacted the area service rep who took a drive with me.  We drove on the freeway and experienced the humming.  He said it was caused by an improperly installed windshield at the factory.  They promptly authorized replacing the windshield which corrected the problem.