Truck Repair: no oil pressure, cummins turbo diesel, low oil pressure

Question
I have a 2000 dodge 24 valve cummins turbo diesel, recently it shut off on me. I thought i had a fuel related problem. however my mechanic informed me that it has no oil pressure that he tested by installing a mechanical gage at the filter. what dianostic steps in which order should be taken at this time?  

Answer
First thing make sure it has oil in the pan.We havent had alot of low oil pressure problems on any 5.9 engines.The oil pump is located behind the frt gear cover.That is what I would do next because the pan is difficult to remove in a Dodge.Pan would be next to check suction tube.