Okay just did some testing mine has the block deals on top of the pumps my main pump seems to be just on all the time type deal tested it out and I get a relief pressure around 2400 psi at 1800 plus engine rpm. Now the second pump which has a line the goes to the steering gear box and then another line goes and tees into the main pumps discharge line I am assuming it is the 2nd stage for the main hydraulics. At low rpm up until about 1500 rpm it will make pressure without moving the controls at 1500rpm roughly it will dump to no pressure. Now... If you roll the bucket back to the stops at low idle then hammer it we see no dump off of pressure it goes right on up to 2400 psi so both pumps feeding the main system show the same pressure above 1500 rpm but help we 1500 rpm the main 1st stage pump will not make any pressure unless you activate a lever. But the 2nd stage will. I'm going to get a video to clear this up a little and post a link