Oil leak on backside of motor

[Chamberpains]

The 2 main culprits are the rear cam cover (very simple fix) or the flywheel housing gasket (very labor intensive because the trans has to come out, rear engine mounts unbolted, oil pan off, engine blocked up)

Other culprits are head gasket leaking and possibly the valve cover leaking in the back.

You next move is to clean all the oil off and have a mirror on a stick to keep checking on it to see exactly were the oil is coming from then running the engine till you can see where it's coming from.