to cushion the transference of the fluid the accumulator 132 is charged with an inert gas such as nitrogen and has a piston therein in the piston 39 s expanded position the accumulator has an amount of pressure approximately equal to the pressure in the overall hydraulic leveling system which is about 90 psig however the accumulator can be compressed such that the pressure therein is on the order of 600 psig excess oil generally is forced into the accumulator when both blade housings 11 and 12 are pulled up as in fig1 it can be seen that by appropriate movement of the leveling valve 128 in response to the level sensor 130 the first and second hydraulic assemblies 117 and 118 are retracted or extended as necessary to maintain the blade housings 11 and 12 in contact with the ground and the frame 3 in a generally upright position the manual side lift valve 160 is provided to override the leveling system so as to force a selected one of the blade housings 11 and 12 into an elevated position such as for changing an associated cutting blade 14 and 15 the manual side lift valve 160 is connected to the filter 145 through a fluid line 185 for recycling of excess oil during a side lifting operation by appropriate manipulation of the side lift valve 160 the leveling system is overridden and fluid is forced.