Dual mode regenerative suspension for an off-road vehicle

A vehicle suspension has one or more hydraulic cylinders (22) connecting an axle to a frame of the vehicle (10) and each cylinder has a first and second chambers (24,26). The suspension operates in either a regeneration mode, in which a fluid path is provided between the first and second chambers (24,26), and a double acting mode, in which the first and second chambers are isolated from each other and fluid flows between each chamber and a separate accumulator (54,60). The selection between the regeneration and double acting modes is made in response to the pressure level in the cylinder as determined by a pressure sensor of a closed loop control system or by the pressure versus current characteristics of a electrically operated valve in the suspension for a loop control system. The hydraulic system also is able to raise and lower the suspension as necessary due to changes in the load carried by the vehicle.