Measuring voltage is one of the most common tests a tractor mechanic will conduct as he troubleshoots a system. The presence of the correct voltage will determine if a component is functioning correctly or not. A common voltage test will be of the battery. A healthy battery should read about 12.5 volts, and a battery that is being charged should measure between 13 and 14.5 volts.
This same principle can be applied if you wanted to build a rear fork lift, 3-point hitch, snow blade set up. Anything! Instead of using a hydraulic cylinder you can use a hydraulic motor and add a PTO shaft to power implements at any location you desire. You can also vary the motor speed by controlling the volume of oil that feeds it. All you need are the 4 basic hydraulic components of reservoir, pump, valve, and device.