The pump is always creating pressure and pushing fluid through the system. The leveling valve maintains the level of the rear end.Self-Leveling-System does this by maintaining pressure or diverting it to raise or lower the rear. When the car is unloaded and sitting at the proper ride height the leveling valve is in the Neutral position. In the neutral position the struts and accumulators are still pressurized which maintain the unloaded height along with the springs. The valve maintains the neutral position pressure in the struts and the accumulators by not allowing the pressure to bleed off and also directs the pressure that the pump is creating to back to the reservoir. When a load is put into the back, the lever arm on the valve is deflected into the fill position which diverts the pressure and fluid flow to the struts and accumulators. This pressure expands the struts which lift the rear until the lever arm is in the neutral position again. A check valve in the leveling valve keeps the increased pressure from bleeding off until the arm is deflect into the return flow position. When the load is removed, the arm on the leveling valve is moved to the return flow position which allows the increased pressure in the system to drain off, until the valve returns to the neutral position and the rear of the car to its normal unloaded ride height.