R520S TRANSMISSION Parts group R520S C00000 MISSION CASE C10000 FRONT AXLE CASE C10200 FRONT AXLE C20000 FRONT DIFFERENTIAL CASE C20200 PLANETARY GEAR (FRONT) C20400 FRONT DIFFERENTIAL C30000 REAR AXLE CASE C30200 REAR AXLE C40000 REAR DIFFERENTIAL CASE C40200 PLANETARY GEAR (REAR) C40400 REAR DIFFERENTIAL C50000 PROPELLER SHAFT sale parts diagram catalog online construction equipment excavator tractor