Today I was normally driving my truck, but I noticed that the oil pressure gauge was reading 75-80. My truck usually reads about 50, is there a problem with it reading so high. What is the normal oil pressure reading for a 6.5. It has never read this high before. Any suggestions?

Your 50 psi pressure sounds normal. The pressure sending unit goes bad often, and it can read high pressure when it goes bad. I installed a mechanical gauge in mine. It is more reliable.

40-45 psi when oil is at normal operating temp, 60-70 psi with cold 15W-40 oil,

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Is the pressure sending unit something that is easy to do? How can I fix this problem? Should my truck be driven without the oil pressure gauge working properly? You help is greatly appreciated.

Can anyone help? Anything is appreciated

OPS is replaceable, on back of the engine center, a little tricky to get at , beside fuel filter but doable, some use a OPS socket, some can't use it, do a search for OPS or oil pressure switch, IIRC there is a thread or 2 with detailed info how to do it.