I have a noise or pull in my front end?

When driving down the road and not in the throttle I have a noise or grabbing of something in front end. I have inspected the brake pads and rotors and they seem to be wearing evenly. I topped of the front differential with about 1/2 qt of fluid. It still does it. I have no sensatition in the front end when in the throttle only when you let off of throttle. Any suggestions CV boots are not torn of cracked.