in fig2 which shows the movement 103 of spool 22 as fluid is pumped to move spool 22 pump pressure builds up along curve 100 in one embodiment any pulsations caused by pump 40 are damped out by transmission through the supply line pressure is built up to pressure 101 to overcome the static friction of seals not shown in sliding sleeve valve 20 in an ideal hydraulic system once the spool 22 begins to move the supply line pressure reduces to line 102 and additional fluid can be supplied at the lower pressure to move spool 22 to a desired position 108 however the entire hydraulic supply line 25 30 is pressured to the higher pressure 101 and expansion of supply line 25 30 results in a significant volume of fluid at pressure 101 instead of the fluid pressure being at level 102 it gradually is reduced along line 107 forcing spool 22 to position 109 and overshooting the desired position 108 to reduce the overshoot issue see fig3 the present invention in one embodiment provides pressure pulses 203 that move spool 22 in incremental steps to the desired position by using pulses 203 the effects of supply line expansion are significantly reduced each pulse 203 is generated such that pulse peak pressure 207 exceeds the pressure 201 needed to overcome the static.