I have a 2004 Dakota with approx. 40K miles. A few days ago I got in it to run an errand and the power steering suddenly felt much stiffer to turn than when previously driven. I checked the fluid and it isn't leaking or low and the belt turning the pump is fine. Tires all have proper inflation. Could ball joints have anything to do with this? I think I read somewhere once that Dakotas like mine were known to have premature failing of the upper ball joints. If not, what else should I look for that might be causing this to happen?