Originally Posted by Biodiesel300TD

The way I understand the system is that the pump is always pumping fluid to the valve in the rear, when the car is running. But when the rear is in a steady state, the fluid being pumped from the pump to the valve is just diverted back to the reservoir. All the pump does is supply pressure to raise the rear. It's not maintaining the height. The valve directs the pressure to raise the rear when needed or directs it back to the reservoir when not needed. If the pump was needed to maintain height then the rear would always sag when the car was turned off.

The SLS is a slow acting system. it takes several seconds for a low rear to raise up. I'd argue that a bump will not cause a major change in fluid flow. There isn't enough time for anything to happen when you hit a bump.