I just clicked on the link below your signature to have a look at the pictures of your truck including the pic of your engine.
You made comments about your PCV valve not being connected to a vacuum source but that the hose just went down behind your engine. You said that you now have connected it to a vacuum source at the intake ( where it should be) correct?
The picture of your engine shows you have a solid oil filler cap on the valve cover but you need a breather type cap.
Your intake vacuum hose to the pcv valve is creating a vacuum inside the engine- sucking oil into the intake.
Put a breather type oil filler cap on and see what happens.
