PROPEL SYSTEM - Continued
10. Manual Brake Release Pump. The manual brake release pump is a manually operated plunger-type that
forces hydraulic oil to the brakes. The manual brake release pump is used when normal means of brake
disengagement are not possible.
11. Cooling Valve. The cooling valve is a two-position pilot-operated valve. Pilot oil from the high pressure side
of the closed loop circuit opens the valve, allowing some of the hydraulic oil in the return side of the closed
loop circuit to be directed to the oil cooler.
12. Propel Gearbox. The propel gearboxes are attached to the drums. The propel motors turn the gearboxes
which turn the drums. There is a brake inside the gearbox that is always engaged until hydraulic pressure
from the brake/shift valves is present.
BRAKE & NEUTRAL
Figure 6. Propel System.