Ok, I am very curious on this. I have seen Cummins videos online and I began to notice that when I turn my key to "run"(engine off), my oil pressure goes up to full operating pressure and not one other truck in those videos have. I'm aware of pre-oilers but I have not seen anthing unusual about the oil lines nor any pump sounds before or after start-up or shut-down. Any ideas?

i am trying to understand... without actully starting(say to turn the radio on) you get full oil pressure?on my 99 2500, it does not show oil pressure until 2-3 seconds after starting(my "check guages" light stays on until it registers oil pressure). as soon as i turn key to "off" my oil pressure stops.also when i start mine, the oil pressure is high(but not maxed out) until it warms up. if it is maxed out after the truck is running you might check the dip stick and see if you are over full.or is it something else?

No matter what, if the key is in the "run" position, not even engine RPM will change it, the needle stays on the last line before the max, period.I have looked before and its right where it needs to be on the dip stick.

Oil pressure sender might just be stuck internally... I would verify this with a mech gauge and see what you pressure actually is... If different then you know you got to replace the oil pressure sender...

That sounds very legit. Thanks for the advice.