Check to see if there is bubbles in the resevoir while running. If so, shut it off, suck the foaming fluid out, put fresh back in. Repeat until all foaming is gone. Any bubbles (foam) will recycle and make noise.I have a 99 duratec but it makes buzzing humming noise inside the car as well as it whones to as well as trans until it full warms up . then its not as noticeable is ther any condioner for power steering pump did a flush used the mercon v motorcraft trans and power steering fluid.