AFTER ASKING I WAS TOLD THAT THE ISSUE IS CALLED CABIN PRESSURE. THIS OCCURS AT ALL SPEEDS OVER 20MPH THE PRESSURE INTERFERES WITH YOUR ABILITY TO HEAR. GIVES YOU ALMOST A HEADACHE IT HURTS YOUR EARS. IT OCCURS WHEN A WINDOW IS ROLLED DOWN MORE THEN 1 INCH. SOMETIMES YOU CAN STOP IT BY ROLLING DOWN ANOTHER WINDOW BUT SOMETIMES YOU HAVE TO ROLL DOWN A 3RD WINDOW TO MAKE IT STOP. IT IS WORSE WHEN THE WINDOW IS ROLLED DOWN 1/4 OF THE WAY OR MORE. *JS