I read your post l will help you fix this this was a problem when the truck had hi hour readings on it.on the right side of the transmission there is a platewith appox 6bolts holding it on drain transmission first than remove bolts take plate off on bottom you will see a filter it has a hole in center you need to take a needle nose plyers and pull filter out of transmission this is the internal filter it is clogged this is why you here the noise from the transmission you need to get new filter and gasket for plate install filter and new gasket on plate and put back refill transmission note if you let go and not change you will burn up transmission it is starving for oil as for pressure reading pump pressure is180psi at1800@rpms forward pressure is 170 psi at 1800rpms same for reverse hope this helps