Had same issue...made big mess in garage and concrete drive. The residual oil press left in supply line will migrate to both the compressor side and turbine side. Yes it it a lot of oil for such a short time being off. You need the 1psi check valve. It will stop 98% of the oil migration the rest you can live with. Often thought could use turbo timer setup to keep return oil pump on for say a min or two after turning ign off would help.

 

OK, definetely gonna get one of these ASAP!! Thanks

 

I used a diode and ran a wire from my interior lights to the trip wire on the oil pump relay. So it runs for 20min after a shut the truck off, doesnt make the fuel pump run. Its helping the matter, but I still have alot of oil in the system. Just a temporary fix