I would tend to agree. The only simple way to rule out the tube is to add 2-4 quarts of oil. This will raise the oil level enough to possibly "cover" the tube if there is a problem with it.Latest on my truck, we have no oil pressure coming into reservoir, i am being told by everyone that this is because of the mechanical gerotor pump, pick-up tube, or check valve. Tried scanner not pulling any codes. Everything and everybody is telling me that the reservoir is filled from below, Dirk you mentioned bad IPR or HPOP if you could give me any other advice or direction I would appreciate it. You got me to check the reservoir in first place. Thanks in advance, also one last note oil presssure gauge does nothing when cranking if that matters. Also makes hollow noise when trying to crank but it has done that before.