Low oil pressure?

I've installed 2 oil temp gauges in older vehicles and my 2011 RAM has this information along with trans temp. Highway driving @ 1800 rpm and the oil gets hot--get off highway oil cools off. It's not a moot opinion its a fact backed up by multiple observations of this many times. This is especially true when on the dyno. Let the engine idle and oil temp will never come up. Put 2000 rpm and some light load on it @ 60-80 hp and oil will come up relatively fast. I've seen 70-80 cold idle pressure drop to 15 or so when oil is hot--this happens when clearances are loose. The HV pump and thick oil are actually exasperating the problem. Don't believe me? Don't care. Hook up a gauge, see for yourself. J.Rob

p.s. It's not air in the line either.