Small Engines (Lawn Mowers, etc.): hydrostatic rear ends, transaxle, rear ends

Question
i am concidering a projcet mower.  the guy says thers a proublem with the rear end.  its a hydrostatic he says theres air in it.  1 how does a hydrostatic rear end work 2 is it even posabil for there to be air in it.  3 how do i fix it

Answer
 Hello Hayden:

 It is Possible for a Hydro Transaxle to get an Air Pocket. However, Most Times the Air will Self Bleed from the System. Send me the OEM and Model Numbers Off the OEM Plate on the Transaxle. I can Locate a Breakdown/IPL of the Transaxle and Better Assist you. It can be Nothing More Than a Sticking Control Valve or it May be a Bad Pump. Thanks.

 Respectfully

 John