[Tom Goldman]

Robbie ,the side port is the line pressure port......Line pressure depends on many factors ,but should be between 165 -200#
Tee into the cooler line to read the pressure on the bottom cooler out line from the trans.
Does the customer do his own transmissions ? ...He may know if the pressure regulator spring was replaced or if any horse shoe shims were added.
If the cooler pressure is high , remove the cooler from the circuit , and measure the pressure on the loop to see if there is a restriction in the cooler raising the pressure.