We have a 2002 DeVille DHS, that has developed a noise that seems to be coming from the drivetrain, wife says sounds like a distant airplane noise that sounds like coming from under car. Everything works properly, no mech. issues. This started out faint but increased, nothing has been changed or repaired on car to point a finger at. Sound does increase as speed or rpm increases. Sounds like a LOUD HUM, let off gas and sound fades, increase gas increase sound. I thought it could be exhaust vibration?? We had a 1994 DeVille that did the exact same thing so we feel it is a common Cadi problem. Does anyone know what in the world this is? PLEASE HELP, Thanks

 

The carrier bearing would make that sound if it was going south. Have you checked out the U-joints??

 

Car is front wheel drive, does not have U-joints or carrier bearing.