ARM 6K5499 - Caterpillar

Illustration 1 g01726276
Rotary actuator during a shift from NEUTRAL to PARK
(1) Body
(2) Stationary vane
(3) Drain passage
(4) Downshift valve
(5) Ball
(6) Passage from downshift solenoid
(7) Ball
(8) Rotor
(9) Rotor vane
(10) Upshift valve
(11) Drain passage
(12) Passage from upshift solenoid
(A) Chamber
(B) Chamber The rotary actuator is controlled by the upshift solenoid and by the downshift solenoid. Pressurized oil from either solenoid flows into body (1). The pressurized oil presses against stationary vane (2) of rotor (8) and against rotor vane (9) of rotor (8). This pressurized oil causes the rotor to turn. Rotor (8) is mechanically connected to the rotary selector spool. The rotary selector spool is part of the selector and pressure control valve. When rotor (8) turns, the rotary selector spool turns.During an upshift, pressurized oil from the upshift solenoid flows through passage (12). This causes upshift valve (10) to move to the left. Drain passage (11) is now closed by the upshift valve. The pressurized oil flows into upshift valve (10). This moves ball (7) to the left and oil flows into chamber (B) between stationary vane (2) and rotor vane (9). This causes rotor (8) to turn in a clockwise direction.The oil that is in chamber (A) on the opposite side of rotor vane (9) presses against downshift valve (4). This causes ball (5) to move to the right side. Oil is then blocked from flowing through passage (6). As the rotor turns, the oil in chamber (A) pushes downshift valve (4) to the right until the valve opens drain passage (3). The oil that is in chamber (A) is now able to drain.When the rotary selector spool and rotor (8) achieve the correct speed position, the transmission gear switch that is connected to the rotary selector spool sends an electrical signal to the Power Train Electronic Control Module (Power Train ECM). The Power Train ECM closes the upshift solenoid stopping the flow of pressurized oil in passage (12). The movement of rotor (8) then stops.During a downshift, rotor (8) moves in a counterclockwise direction. Pressurized oil from the downshift solenoid flows through passage (6). Downshift valve (4) is moved to the left closing drain passage (3). The pressurized oil from passage (6) goes into downshift valve (4). The pressurized oil moves ball (5) to the left and oil flows into chamber (A). This causes rotor (8) to turn in a counterclockwise direction.The oil that is in chamber (B) presses against upshift valve (10). This causes ball (7) to move to the right stopping oil from going through passage (12). As the rotor turns, the oil in chamber (B) pushes the upshift valve to the right until drain passage (11) is open to chamber (B).When the rotor achieves the correct speed position, the Power Train ECM deactivates the downshift solenoid. Pressurized oil in passage (6) is stopped, stopping the movement of rotor (8).When the transmission is in the NEUTRAL position, rotor (8) is in the position that is shown. The downshift solenoid is always activated in the NEUTRAL position so