I followed cable back from lift control knob to a unit which I assume is the main control valve---this has a selector unit on it with three positions--two dimples and a slot--with a ball locator-- noticed the ball was only half in slot---repositioned and recharged system marked tires with chalk as reference--the above unit is fed by a hose from a unit in front---which has fluid in it ---QUESTION--what is this fluid and how high in the resevoir should it be ---it appears to be down the bottom and fairly empty

------------------
syd 81.300SD
72.300SEL 4.5