Axle driving apparatus

An axle driving apparatus comprising:

• a transmission casing, said transmission casing including an upper casing and a lower casing joined together to form an enclosed transmission;
• a center section enclosed within said transmission casing, said center section supporting a hydraulic pump and a hydraulic motor;
• a closed fluid path for transfer of fluid between said hydraulic pump and said hydraulic motor provided within said center section, said closed fluid path being subjected to fluid pressure from said hydraulic pump to rotate said hydraulic motor;
• a suction port provided at a lower surface of said center section along said closed fluid path for providing fluid from said transmission casing to said hydraulic pump for rotating said hydraulic motor;
• first and second check valves disposed at an opening of said suction port, said check valves being simultaneously opened by a control means, wherein fluid within said closed fluid path is dischargeable from said center section through said check valves to an oil tank, and wherein said hydraulic motor is freely rotatable;
• and
• means for filtering fluid from said transmission casing disposed at an opening of said suction port, said filter means being fitted between said center section and said lower casing.