If the noise is only whenthe tub is filling, then it must be the diverter spout, since that is the only portion of the system not also used when the shower it operating. The old one unscrews, or unclamps if there is a screw on the lower right side of it, and the new one replaces it. Just take the old one with to get a new one with same connection dimension.: There is a loud noise when filling the tub with water – noise can be heard throug hout house. When valve is lifted to shift water to shower, noise stops. Is problem the diverter valve in spigot or something else? If diverter valve, can it be replaced and if so, how does one do it? Any help you can offer would be much appreciated. House is 12 years old.