required to act as a storage receptacle of fluid during wheel articulation motions as the fluid is primarily pumped directly to and from the tank and is not transferred to other locations within the same circuit when the present system is used as an active suspension systems the load distribution unit 18 need only be large enough in size to sense the relative pressures of the two pairs of diagonally opposite wheel valves and to cause the movement in the spool valve 31 which in combination with the location of the wheel valves 34 to 37 permit the intelligent introduction or removal from the appropriate circuits of fluid even at high speed in conventional active suspension systems weight distribution adjustments are not normally made as a result of axle articulation motions and relative motions of diagonally opposite wheels but are rather calculated individually on the basis of the position of each individual wheel with reference to the position of the chassis and road the advantage of using the present system in a more active suspension context is that it is sometimes advantageous to not permit an interaction of wheels as in the slow passive system in the previous proposal it has been assumed that the pump is switched on when corrections to the height or and voluntary tilt trim attitude changes need to be made this therefore requires that the vehicle is given a wide spectrum of what has to be considered an acceptable height and trim inclination for most of.