Apparently squeaky leaf springs on F-150 and F-250 had been a TSB(technical service bulletin) for years now and the cause of the creaking or squeaking you hear from the rear of your truck is caused by the 8 (4 each side) Anti-friction pads or "contact points" on the leaf springs binding and vibrating over bumps or really any time you flex the leaf springs. It's apparent that the Raptor's softer suspension really compounds the problems Ford has had with their leaf packs in the past.
The solution is to simply lift your truck from the frame so the suspension completely drops- giving you access to the leaf springs and contact points(pictured below). The product to use is Dupont Teflon Grease(Severe Service) and smear it, glob it all over the contact points...then just lower the truck down. This method is the only solution and should be good for 3000-5000 miles of service!!
The solution is to simply lift your truck from the frame so the suspension completely drops- giving you access to the leaf springs and contact points(pictured below). The product to use is Dupont Teflon Grease(Severe Service) and smear it, glob it all over the contact points...then just lower the truck down. This method is the only solution and should be good for 3000-5000 miles of service!!