PUMP GP-GOV & FUEL INJ 2W3371 - Caterpillar

Illustration 1 g03476321
(1) Solenoid
(2) Ball
(3) Orifice
(4) Chamber
(5) Clutch fill port
(6) Control spool
(7) Spring
(8) Oil supply port
(9) Drain port Control of an individual clutch in the planetary transmission is achieved by the use of a modulating valve that is controlled by a solenoid.Pressurized oil is supplied by the transmission pump to the modulating valve through oil supply port (8). Pilot pressure is allowed through control spool (6) to chamber (4). The oil in chamber (4) is allowed to drain to the sump through orifice (3) and drain port (9). When a gear is selected and solenoid (1) is energized, ball (2) is forced against orifice (3). The pressure of the oil in chamber (4) increases. The increased pressure moves control spool (6) to the right against spring (7). Pressurized oil is allowed to flow to the clutch through clutch fill port (5).When solenoid (1) is de-energized, the pressure of the oil in chamber (4) unseats ball (2). The oil in chamber (4) is allowed to drain to the sump through orifice (3) and drain port (9). As the pressure in chamber (4) drops, control spool (6) is moved back to the left by spring (7). As the control spool is returned to the left, the supply of oil from oil supply port (8) is blocked. The oil in the clutch is allowed to flow to the sump via drain port (9).