I've been losing oil in my Cherokee ('97 4.0L AX15 4x4). It loses at least one quart every 500 or so miles. I've never seen any drips on the ground, ever. However, I do have oil all over the back side of the engine and the transmission. I replaced the oil filter adapter o-rings and the valve cover gasket, but I still lose oil like before. I don't think I'm burning too much, because I just passed an emission inspection. Any idea what I should be checking? Rear main seal maybe? Is this something I should worry about, or should I just keep feeding it oil? I use 10w30 by the way. Thanks!