Well, you might want to have a look at the balljoints. I know on my f-i-l's Lincoln Town Car that he had several years back, it was a really bad creaking, people would run away from the car, it literally sounded like the front end was going to pull out from under it. This only happened when the wheels were turned hard left or right. No one could get a handle on what was wrong until a little old lady, whose father used to run an airport livery, was walking by and said that when she worked for him (back in the '40s), whenever a car started acting like that, he'd just shake his head and say, "Balljoints." Turned out that was exactly what was wrong with my f-i-l's Lincoln. Replaced them, fixed it. Worth a look, maybe?
"...a long habit of not thinking a thing wrong, gives it a superficial appearance of being right, and raises at first a formidable outcry in defense of custom. But tumult soon subsides. Time makes more converts than reason." Thomas Paine