The tractor motor return circuit is designed for flow and can significantly lower the back pressure of the return side of the motor circuit versus directing return flow through the motor circuit SCV (if a motor return port is not available). Since the hydraulic motor seal may be exposed to the motor return flow, the lower back pressure of the motor return circuit can be beneficial to motor seal integrity.
Hydraulic motor return couplers are typically opened when coupled (do not require reverse flow to open).
3. Connect the case drain line to the case drain tractor coupler.
Refer to the following illustrations as examples of a John Deere and competitive tractor:
NOTE: Case drain port coupler not shown on John Deere tractor photo.