STEERING COLUMN GP 1125706 - Caterpillar

Manifold
Manifold valve assembly (9) connected across the main circuit contains two pilot operated high pressure relief valves cartridges (8). The pressure relief valves prevent high pressure surges in either side of the circuit by dumping oil from the high to the low pressure side. High pressure surges may occur during rapid acceleration or braking, or with sudden application of a load.The manifold valve assembly also contains shuttle valve (10) and a charge pressure relief valve (7). The shuttle valve establishes a circuit between the low pressure side of the main circuit and the charge pressure relief valve. The relief valve then can dump excess cooling oil added by the charge pump into the motor case, and control the charge oil pressure. The oil flows from the motor case to the pump case to tank.Cooling Circuit
Excess charge oil (cooling oil) from the charge pressure relief valve in manifold valve assembly (9) enters the motor case. The charge oil flows through the case drain lines to the pump case. The charge oil then flows through the pump case, and to the tank cooling the components of the closed loop system.When the pump is in neutral, the shuttle valve is centered. The excess flow from the charge pump is directed to the cooling circuit by the charge relief valve in the charge pump. Cooling flow is not admitted to the motor case. The oil flows through the pump case to the tank.Transmission Operation
The transmission is a mechanical three speed transmission that is manually shifted into each of the three speed ranges. The transmission contains an electric/hydraulic shift lock circuit. This prevents the transmission from being accidentally shifted. The transmission has a neutral position between the low and second speed ranges. Another neutral position is between the second and high speed ranges.
Transmission
(1) Outside lever. (2) Inside lever. (3) Case. (4) Fork assembly. (5) Shift rail. (6) Main shaft. (7) Main shaft slider gear. (8) Input gear and shaft. (9) Main shaft low gear. (10) Countershaft driven gear. (11) Countershaft second gear. (12) Countershaft. (13) Countershaft low gear.Outside lever (1) and inside lever (2) swivel on case (3). They move fork assembly (4) back and forth on shift rail (5). The fork assembly slides the main shaft slider gear backward and forward on the main shaft. Main shaft slider gear (7) is splined to main shaft (6). When the main shaft slider gear is meshed with another gear, power from the hydraulic motor is transferred through the second gear to the main shaft. The transmission output speed and torque are determined by the gear train engaged within the transmission.
Transmission Shifted Into LOW
(6) Main shaft. (7) Main shaft slider gear. (8) Input gear and shaft. (9) Main shaft low gear. (10) Countershaft driven gear. (13) Countershaft low gear.When the transmission is shifted into the LOW speed range, main shaft slider gear (7) is moved to mesh with main shaft low gear (9). Power is transmitted from input gear and shaft (8), through countershaft driven