F.P.TAKE-OFF G 8F4062 - Caterpillar

LOW SPEED
Illustration 7 g02397496
Left travel motor (LOW SPEED) (4) Travel speed solenoid valve (5) Pilot line (15) Pressure sensor (idler pump) (18) Passage (20) Displacement change valve (23) Counterbalance valve (25) Left travel motor (26) Swashplate (27) Motor rotary group (28) Passage (29) Swashplate control piston (30) Passage (return oil) (50) Pilot pump (51) Idler pump (56) Travel speed control switch (58) Left travel lever/pedal (A) Indicator for HIGH SPEED (B) Indicator for LOW SPEED (C) Machine ECMWhen travel speed control switch (56) is set at the LOW SPEED position, an electrical signal is sent to machine ECM (C) . The engine and pump controller does not energize travel speed solenoid valve (4) and pilot system oil pressure flows through pilot line (5) to displacement change valve (20) . The spool in the displacement change valve shifts downward. A portion of the oil flow from the idler pump in passage (18) flows through displacement change valve (20) and passage (28) to swashplate control piston (29) . As a result, swashplate control piston (29) moves swashplate (26) to the maximum displacement position. At the same time, the oil that acts on swashplate control piston (29) flows into the case drain of the travel motor. One rotation of motor rotary group (27) displaces a larger amount of oil flow. The rotational speed of the left travel motor decreases. The left track moves slowly and better traction is achieved.The return oil from motor rotary group (27) flows through passage (30) , counterbalance valve (23) , line (44) and swivel (45) . The return oil then flows through line (6) , left travel control valve (11) , return passage (9) and return line (48) to the hydraulic tank.Right travel motor (35) receives the oil delivery from the drive pump. The right travel motor functions in the same manner as the left travel motor in the LOW SPEED position.HIGH SPEED
Illustration 8 g02396377
View of pilot manifold from underside of machine (4) Travel speed solenoid valve
Illustration 9 g02397697
Left travel motor (HIGH SPEED) (1) Left travel motor (2) Swashplate (3) Motor rotary group (5) Swashplate control piston (6) Passage (return oil) (13) Passage (18) Displacement change valve (19) Passage (23) Counterbalance valve (27) Pilot line (43) Pressure sensor (idler pump) (44) Idler pump (50) Pilot pump (51) Travel speed solenoid valve (56) Travel speed control switch (58) Left travel lever/pedal (A) Indicator for HIGH SPEED (B) Indicator for LOW SPEED (C) Machine ECMWhen travel speed control switch (56) is set at the HIGH SPEED position, an electrical signal is sent to machine ECM (C) . Pressure sensors (15) and (14) also send an electrical signal to the engine and pump controller. If the travel load is light and when the pump delivery pressure is below a certain pressure, the engine and pump controller energizes travel speed solenoid valve (4) . Pilot system oil pressure is blocked from travel speed solenoid valve (4) . The spool in the displacement change valve shifts. A portion of the oil delivery from the