power steering pump?
 

When I am going slow, my steering will get very difficult, especially when parallel parking. It also makes a loud noise that I've noticed every ford truck makes when turning slow, except a lot louder. My fluid has always been fine, but I wouldn't doubt that the steering pump is shot. Its been progressivly getting worse over the past year or so. Rarley, the steering will kick back in and is very nice. I am almost positive it is the pump, but it could be the gear box, or both. Any opinions?