Mine came from southern Ill and I grew up in SE Iowa but if you brought it here, it'd be a tad further.
What you said is interesting about the clutch valve:
This should not happen and is contrary to the design. It only vents the engaged clutch and preserves the nominal pressure in the system.One thing that I noticed was the buzzing noise stopped and the pressure dropped as soon as I pressed the clutch
An even 60 psi at the cooler inlet says (to me anyway ) this cooler - lube circuit is kind of working at it should, though it may not be getting enough flow. If its the pressure regulator valve that's buzzing, the cooler bypass valve seems to be compensating correctly in either pushing the flow to the cooler, or modulating the pulsations produced by the pressure regulator valve slamming back and forth and giving the appearance of a constant pressure at the cooler inlet.When the clutch pedal is depressed, the clutch
valve lifts, dumping oil from the engaged clutch. The
same motion in the clutch valve seals off passages in
the valve housing, retaining oil supply in valves and in
front of accumulator. The check valve ball also closes
and holds pressure at other end of the circuit.
When the clutch pedal is released again, the clutch
valve drops and oil retained in the valving goes to
work again with only a slight delay.
Another valve might be buzzing too. I've been trying to contemplate what might happen if one of the check balls when missing.
On the fun side, I did get to dig a hole with mine yesterday. Didn't get the stump out yet but I made a big mess.
Mine still doesn't like shifting into low sometimes. With all this great talk on how these things work, I'm going to have to get a pressure gauge on mine just to see what's happening.