PUMP & MTG GP-MAIN HYDRAULIC 2434073 - Caterpillar

Travel Reverse
Illustration 5 g03387338
Travel hydraulic schematic - Reverse Travel
(1) Left travel control lever
(2) Right travel control lever
(4) Left travel motor
(5) Right travel motor
(9) Pilot oil distribution block
(10) Hydraulic tank
(11) Oil cooler
(12) Slow return check valve
(13) Main pump
(14) Pressure limiting valve
(15) Pilot manifold
(16) Travel speed control solenoid
(17) Hydraulic lockout solenoid
(18) Line (pilot)
(19) Line (pilot)
(20) Line (supply oil)
(21) Pressure compensator
(22) Load sense spool
(23) Load sense passage
(24) Parallel feeder passage
(25) Main control valve
(26) Right travel control valve
(27) Mechanical linkage
(28) Passage
(29) Load sense control valve
(30) Left travel control valve
(31) Mechanical linkage
(32) Passage
(33) Load sense control valve
(34) Passage
(35) Passage
(36) Orifice
(37) Passage
(38) Passage
(39) Line
(40) Line
(41) Line
(42) Line
(43) Swivel
(44) Line (case drain)
(45) Passage
(46) Counterbalance valve
(47) Passage
(48) Passage
(49) Displacement change valve
(50) Ball resolver
(51) Swashplate
(52) Swashplate control piston
(53) Passage
(54) Line (pilot)
(55) Line (pilot)
(56) Passage
(57) Swashplate control piston
(58) Swashplate
(59) Ball resolver valve
(60) Displacement change valve
(61) Passage
(62) Passage
(63) Counterbalance valve
(64) Passage Pilot Oil Circuit
Oil flow is supplied to the pilot system from main pump (13). Main pump (13) sends oil flow through main control valve (25) and into pilot manifold (15). Pressure limiting valve (14) inside pilot manifold (15) reduces the oil pressure from main pump (13). This action creates the pilot oil pressure.When the hydraulic lockout switch is placed in the UNLOCKED position, pilot oil flows through hydraulic lockout solenoid (17) and into line (18). Pilot oil then flows through pilot oil distribution block (9) and into main control valve (25). Pilot oil shifts load sense spool (22) downward. Load sense spool (22) allows oil in load sense passage (23) to flow to main pump (13).The travel speed can be controlled through fine movements of travel control levers (1) and (2). The travel speed can also be set to LOW SPEED or HIGH SPEED by using two-speed travel switch (3). The machine will travel at LOW SPEED until the operator slides the switch to the HIGH SPEED position. The machine will then move into HIGH SPEED mode. The HIGH SPEED mode is recommended for travel on a flat surface. During gradual downhill travel, the mode may be set to HIGH SPEED for high mobility.Reference: For more information on how the high speed function operates, refer to Service Manual, "Travel Motor"When the operator sets two-speed travel switch (3) to the HIGH SPEED position, travel speed control solenoid (16) energizes. This action allows pilot oil to flow through travel speed control solenoid (16), through line (19), and through swivel (43). The pilot oil then split into two paths. The first path the oil flows is through line (55). into right travel motor (5), and to change displacement valve (60). This action will shift change displacement valve (60). The second path the oil flows is through line (54), into the left travel motor (4), and to change displacement valve (49). This action shifts change displacement valve (49).High Pressure Oil Circuit
Left Travel Motor Circuit
Main pump (13) sends oil flow into main control valve (25). Oil then flows into parallel feeder passage (24) and to left travel control valve (30). When the operator moves