Has anyone ever replaced the locating key on the wiper arm spline? I have never been able to source one with a part number. Local Ford dealers can't. Every Super Duty I owned had them but they fall out. They usually fall in the cowl valley. and can be reinstalled some time they just disappear. The parts counter says if its not a part number I don't need it. I showed one parts guy and he took one off a new truck and gave it to me.