Your jacks are most likely Power Gear. The valves are located on top of the fluid reervoir which is probably located in the curb side far back compartment. You can check for fluid leaks by inspecting the valve body to see if there is any wet fluid there. If not your problem might be the reservoir is low enough on fluid that you are hearing air in the system. To check this, retract the jacks until they are completely up. Then remove the fill plug on the side of the regulator. It is the plug that doesn't have wires going into it. If the fluid level is not up to the bottom of the plug hole, fill the reservoir with the recommended fluid. Run the jscks all the way down, then retract them . This should remove any air in the system. You may have to do this a couple of times. Hope this fixes the problem.
Jim and Lynda, (Sophie, Jake, attack trained killer Shi-Tzus :-))
2003 Fleetwood Expedition 38N 2005 Saturn Vue