As said, with the 4.0L valve cover can come loose and leak down the back. Also oil filter assemblies can seep oil, or your oil sending unit as well could seep oil. I'd say clean your engine really well, and then examine for leaks to try to pinpoint where it's coming from. It's also possible the front of the oil pan is seeping, and blowing back, but if so, you should be able to see it underneath on the oil pan.
The beatings will continue until attitudes improve!
HID Quad bi-xenon + foglight retrofit