I agree, sounds like the end links. The ends are ball joints that are not greasable, and dry out over time, then they wear and knock. Ford dealers stock the links. I paid about $15 each last spring. Parts stores can get McQuay Norris or Moog links, and I know that one style has grease fittings.
When you replace them, make sure that the wheels are even, either on ramps or hanging. This eliminates the torsion in the sway bar. Two integral bolts with nuts hold them in. Unbolt tops from both sides first. This allows the whole sway bar to swing down so you get clearance to the lowers. You will see how that works when you get into it. Dealers will install them for about 2 hours labor. Of course, it takes them a whole lot less. Now that I have done one set, I can replace both in 45 minutes, if I don't have to hunt for the tools.