PUMP GP-TRACTION 0844899 - Caterpillar

Illustration 1 g01033751
Rotary Actuator (Shift from NEUTRAL to REVERSE) (1) Body (2) Stationary vane (3) Drain passage (4) Downshift valve (5) Ball (6) Inlet from downshift solenoid (7) Ball (8) Rotor (9) Vane of rotor (10) Upshift valve (11) Drain passage (12) Inlet from upshift solenoid (13) Chamber (14) Chamber (AA) Pump oil (BB) Drain oilThe rotary actuator is controlled by the upshift solenoid and the downshift solenoid. Pressure oil from either solenoid flows into body (1) and pushes against stationary vane (2) and vane (9) of rotor (8). The pressure oil causes rotor (8) to turn. Rotor (8) is connected to the rotary selector spool of the selector group. Rotor (8) causes the rotary selector spool to turn.During an upshift, pressure oil from the upshift solenoid flows through inlet (12). Upshift valve (10) will move to the left as a result of the pressure oil flowing to inlet (12). Drain passage (11) is now blocked by upshift valve (10). The pressure oil flows into upshift valve (10). The pressure oil moves ball (7) to the left. The pressure oil then flows into chamber (14) between vanes (2) and (9). This causes rotor (8) to turn in a clockwise direction.The oil in chamber (13) pushes downshift valve (4). The push will cause ball (5) to move to the right side. The oil is not allowed to flow out of inlet (6). As the rotor turns, the oil in chamber (13) pushes downshift valve (4) to the right until the valve opens drain passage (3). The oil in chamber (13) is now available to drain.When the rotary selector spool and rotor (8) obtains the correct SPEED position, the transmission switch delivers an electrical signal to the transmission control. The transmission control deactivates the upshift solenoid. This blocks the flow of pressure oil in inlet (12) and the movement of rotor (8) stops.During a downshift, the movement of rotor (8) is in a counterclockwise direction. Pressure oil from the downshift solenoid flows through inlet (6). The pressure oil will cause downshift valve (4) to move to the left. This blocks drain passage (3). The pressure oil from inlet (6) flows into downshift valve (4). The pressure oil moves ball (5) to the left side. The pressure oil then flows into chamber (13). This causes rotor (8) to turn in a counterclockwise direction.The oil in chamber (14) pushes upshift valve (10). This causes ball (7) to move to the right. The oil is not allowed to flow out of inlet (12). As the rotor turns, the oil in chamber (14) pushes the upshift valve to the right until drain passage (11) is open to chamber (14) .When the rotor obtains the correct SPEED position, the transmission control deactivates the downshift solenoid. The pressure oil in inlet (6) is now blocked. This stops the movement of rotor (8) .When the transmission is in NEUTRAL, rotor (8) is in the position that is shown in the illustration. The downshift solenoid should always be activated