Welcome to the wonderful world of Ford pumps. The issue is almost always air. Though I have worse problems with newer ones, the older ones always were fun too. The way I do it is to apply a vacuum to the fill hole with an old a/c vacuum pump I modified. it pulls the air out of the pump right now. Most don't have access to one of these but you might find a mechanic who does as this was actually a recommended procedure on 2000 and above Ford (and GM). Alternate way to get ahead of it is to let it sit, refill it, jack it up and turn the wheels back and forth without starting it, let the foam settle, top of as necessary and repeat the procedure. Then start it for any a couple of seconds, let the foam settle and top off, repeat as necessary. After you get it running you may still have a whine which requires shutting off and letting sit for about 20 minutes to let the foam settle. (Now you see why I prefer the vacuum method). If after all this you still have a noise, either you have a defective pump or a restriction in the return line or reservoir.
