also check the suction hose to the pump for a couple of things,first they had a bad batch of hoses so they would either kink or delaminate internally,know about this first hand,secondly make sure the suction hose and the oil cooler return are connect to the fittings at the bottom of the tank at opposite ends(or the case drain line is between them)on some planters if the lines go into the tank side by side it sets up a swirl effect or causes the oil to foam or something,and it will make it pulse.