VALVE GP-PILOT 1315914 - Caterpillar

and holds piston (10) against the plates of the forward clutch and the clutch is engaged.
DUMP VALVE OPERATION (Clutch Engaged Position)
12. Plunger. 13. Passage (to clutch piston). 14. Inlet passage.With the control valve in the REVERSE position, the hydraulic oil moves through tube assembly (2), through hydraulic passage (6) in the spider assembly which goes to the dump valve (4) for the reverse clutch. The dump valve sends the pressure oil to the piston for the reverse clutch, which engages the reverse clutch. Dump valve (4) is same as dump valve (11) and operates in the same way to engage or release the clutch.
DUMP VALVE OPERATION (Clutch Not Engaged)
12. Plunger. 13. Passage (to clutch piston). 15. Outlet passage.When the control valve is moved to NEUTRAL position, oil is not sent to a clutch. With no oil pressure to hold plunger (12) toward the clutch, the centrifugal force caused by clutch rotation moves plunger (12) out. This opens oil passage (13) to a clutch piston and to outlet passage (15). As the oil from the piston goes through the outlet passage, springs in piston and cylinder assembly move the piston away from the clutch plates and the clutch releases.Control Valve in NEUTRAL
CONTROL VALVE (Neutral Position)
1. Control valve body. 2. Directional spool valve. 3. Springs. 4. Port to oil cooler. 5. Oil inlet port. 6. Relief valve. 7. Check valve.The control valve is fastened at the rear of the marine transmission. This valve sends and controls the flow of oil to the transmission. The pressure control section of the valve gives automatic control of the pressure, with a slight delay effect to give a smooth flow of power as it goes from NEUTRAL to either FORWARD or REVERSE.With the engine running and the directional valve (2) in the NEUTRAL position, the oil flow through the control valve is as follows:Oil flows from the filter to inlet port (5), around the stem of relief valve (6) and through a passage to the NEUTRAL chamber of directional spool (2). The oil is stopped at the directional spool. The oil pressure in the control valve goes up and opens check valve (7). The oil fills the chamber below the relief valve. When the oil pressure in the chamber is higher than the pressure of springs (3), relief valve (6) opens. The oil flows out through port (4) to the oil cooler.Control Valve in FORWARD Position
With the engine running and directional valve (6) in the forward position, the oil flow through control valve body (1) is as follows:Oil from the filter flows to inlet port (14), around the stem of relief valve (16) and through a passage to directional spool valve (6). The oil flows around the spool valve and out port (9) to the forward clutch. The oil also moves ball check valve (11) against its seat and goes on to main check valve (5). The oil moves check valve (5) against stop (3). The oil flows through small holes in the four