TURBOCHARGER GP 7C4330 - Caterpillar

DUMP VALVE (Clutch Disengaged Position)
12. Plunger (held out by centrifugal force). 13. Passage (to clutch piston). 15. Dump passage.Movement of the control valve to the REVERSE position directs the hydraulic pressure oil through the tube assembly in top shaft (2), through the hydraulic passage in the spider assembly which leads to the (not shown in the cutaway) astern clutch dump valve (5). The valve directs the pressure oil to the astern clutch piston which engages astern clutch (7). Dump valves (5 and 11) are identical and operate in the same manner to either engage or disengage a clutch.When the control valve is moved to NEUTRAL position, the pressure oil is no longer directed to a clutch. With no oil pressure to hold plunger (12) inward, the centrifugal force of the rotating clutches moves plungers (12) out. With the plunger out, oil passage (13) to a clutch engaging piston is open to dump passage (15). As the oil from the piston dumps, springs in the piston and cylinder assembly move the piston away from the clutch plates and the clutch disengages.Control Valve
NEUTRAL Position
The control valve is on the right side of the marine transmission. All of the oil from the pump, when the engine is running, goes into the control valve. The lever on the control valve has three positions which are: AHEAD (forward), ASTERN (reverse) and NEUTRAL.
CONTROL VALVE IN NEUTRAL POSITION (Engine Running)
1. Control valve body. 2. Selector spool. 3. Springs (relief valve). 4. Outlet passage (to oil cooler). 5. Inlet passage (from filter and pump). 6. Relief valve. 7. Poppet.The NEUTRAL position of the control lever keeps selector spool (2) in a position where the pump oil through inlet passage (5), and a passage in valve body (1), goes to a chamber with no outlet to the clutches. The pump oil also goes through a passage in relief valve (6) thru orifice in dampening poppet (7). With no outlet for the pump oil in the control valve the pressure of the pump oil increases. Pump oil pressure of 35 5 psi (240 35 kPa) opens relief valve (6) since the force in the dampening poppet (7) chamber of this valve (6) is greater than force of springs (3). As relief valve (6) opens pump oil goes thru outlet passage (4) thru the oil cooler and thru the lubricant passages in the transmission.AHEAD Position
The AHEAD (forward) position of the control lever keeps selector spool (2), in a position where the pump oil through inlet passage (5), and a passage in valve body (1), goes through passage (16) to the ahead clutch. The pressure of the pump oil must increase to engage the clutch. The pump oil in passage (16) also moves ball (15), goes into check valve (11) and moves the check valve against stop (9). The pump oil is metered gradually thru the check valve orifice and into load piston (8) cavity. Pump oil flow thru passage (16) to ahead clutch fills the clutch piston