Propel Pump in Forward Position
Forward, Low Speed With Parking Brake Off
(1) Flushing valve. (2) Charge relief valve. (3) Line from charge filter. (4) Tandem propel pump. (5) Axle propel motor. (6) Servo control valves. (7)
Drum drive motor. (8) Brake interlock valve. (9) Unfiltered charge oil. (10) Parking brake and speed shift valve. (11) Thermal bypass valve. (12)
Hydraulic oil tank. (13) Line from charge filter relief. (14) Hydraulic oil cooler. (15) Axle motor flushing valve. (16) Drum motor flushing valve.
When the parking brake button is pulled out (released), the
parking brake and interlock valves (8) are energized. The
parking brake valve shifts to the right. Charge oil goes to the
parking brake and moves the piston against the spring force
and releases the parking brake. The interlock valve shift to the
left when energized. The passage for each side of the pump
control piston is now separated and the swashplate will move
when oil is directed to one side.
When the operator moves the propel lever to the FORWARD
position, servo control valves (6) shift from the neutral position.
Filtered charge oil enters the pump at line (3). Charge oil flows
through the control valves to the servo-pistons, causing the
swashplates to rotate.