GEAR-SUN 5392450 - Caterpillar

OIL FLOW IN THE NEUTRAL POSITION
1-Selector valve body. 2-Directional spool valve. 3-Pressure regulating springs. 4-Port to oil cooler. 5-Oil inlet port. 6-Bypass valve. 7-Damping valve.Oil flows from the filter to inlet port (5), around the stem of bypass valve (6) and through a cored passage to the NEUTRAL chamber of directional spool (2) where it is blocked. As the oil cannot flow on from the NEUTRAL chamber, the oil pressure rises. Pressure oil opens damping valve (7) and fills the bottom portion of the bypass valve. When the pressure behind bypass valve (6) is great enough to overcome springs (3), the bypass valve is forced open (up) and oil passes out of the control valve through port (4) to the oil cooler.Selector Valve in Ahead Position
With the engine running and the directional valve (6) in the AHEAD position, the oil flow through the selector valve body (1) is as follows:Oil from the filter flows around the stem of bypass valve (16), through a passage in the directional spool valve to the ahead clutch port (13). At the same time, oil forces ball check valve (11) against its upper seat and the oil flows on to main check valve (5). The oil forces check valve 5) against stop (3), flows through small holes in the four plugs in the bore of the check valve and flows through orifice (4) of check valve (5). The oil from the orifice flows to the end of load piston (2) and compresses pressure regulating springs (10) until the force of the load piston and the bypass valve force balance. Bypass valve (16) regulates the maximum clutch engagement pressure while check valve orifice (4) provides a gradual pressure build up to assure smooth clutch engagement. As oil enters the engaging clutch cavity, oil pressure also increases behind load piston (2) forcing it down. When clutch engagement pressure is reached, the bypass valve moves upward and oil not needed to maintain clutch engagement flows through port (12) to the oil cooler.
OIL FLOW IN THE AHEAD POSITION
1-Selector valve body. 2-Load piston. 3-Stop. 4- Orifice. 5-Check valve. 6-Directional spool valve. 7-Port to sump. 8-Port to sump. 9-Port to astern clutch. 10-Pressure regulating springs. 11-Ball check valve. 12-Port to oil cooler. 13-Port to ahead clutch. 14-Oil inlet port. 15-Port to sump. 16-Bypass valve.Any oil which may leak by the directional spool (6) returns to the sump through return ports (7) and (15).When the directional spool valve is again moved to NEUTRAL, oil in the ahead clutch drains through the dump valve to the sump. The decrease in pressure allows the ball check valve to move from its seat and the oil behind check valve (5) flows out to the sump through port (7). Since the pressure on the bottom side of check valve (5) is now less than the pressure on top of the check valve, the pressure oil on top of the load piston pushes the check valve open and allows the oil to flow out port