This is a weird one. I have a 1996 2500 5.9 bone stock with 217,000 miles. Engine has been maintained well. My problem is driving down the road oil pressure is about 45 psi. If pulling a hill and auto trans shifts down, oil pressure drops to about 15 psi on stock gauge???? Engine seems strong, but I am concerned with this. when trans shifts back into overdrive oil pressure goes back up. Just the opposite of what it should do. I have not put a mechanical gauge in yet to test. It seems like maybe oil pump pickup tube may be cracked. Has anyone had this problem?

 

I would def check it with a mechanical gauge to rule out the possibility of the sensor being bad.

 

i had a 97 that did that turned out to be a cracked block

 

Ok... I installed manual gauge at filter mount and pressure is good through all rpm! Manual reads high when demand is high. gauge on dash reads low. sending unit or gauge? Thanks to those who posted I really appreciate it...

 

The sending units are known for going bad. I'd put my money there. Make sure you buy a Cummins one, I hear the parts house brands don't last very long, and it's a tough job.

 

Yep. Mine was okay. But a buddy of mines will read normal, and then randomly drop to zero and the check guages light will come on. It scared the crap out of me the first time I drove his truck.

 

Mine did the same exact thing.

 

Its scary if you've never seen that happen before, especially when its not your vehicle. No I usually just ignore it because I'm used to it! He doesnt plan on changing it either