I have a 2003 Ford Expedition-it's been riding rough lately. I took it for an oil change and had 4 new tires put on it. It has 47,000miles. The auto shop said that it is riding rough because the 4wd is not disengaging. I have an appointment to take it to a Ford dealer next Weds. Trying to find out if this is something I can correct....? would it still be under warranty?