Hi! If you haven't replaced your valve cover gasket in the last 3 years, I'd probably start with that, because it is easy to do and inexpensive. The way the engine is placed makes it very prone to leak oil in the area between the engine and the gearbox. Jesse has plenty of videos on that. Then, I'd clean everythig with brake cleaner and look again a few weeks later to confirm if there is new oil or not. Otherwise, it might be a big big job to do the pan gasket and-or the rear main seal. Have fun with your XJ6!
