784B Tractor and 785B Off-Highway Truck Power Train Caterpillar

Schematic for the transmission hydraulic system

(1) Suction screen

(2) Transmission section of the hydraulic tank

(3) Lockup clutch solenoid

(4) Downshift solenoid

(5) Upshift solenoid

(6) Rotary actuator

(7) Transmission scavenge pump section

(8) Transmission lubrication section of the oil pump

(9) Transmission charging pump section

(10) Passage to the relay valve in the lockup clutch and synchronizing valve

(11) Transmission lubrication hydraulic filter

(12) Transmission charging hydraulic filter

(13) Priority reduction valve

(14) Neutralizer valve

(15) Rotary selector spool

(16) Selector and pressure control valve

(17) Transmission oil cooler

(18) Transmission oil cooler inlet relief valve

(19) Magnetic screen

(20) Transfer gears and transmission case

(21) Transmission lubrication relief valve

(22) Dual stage relief valve

(23) Selector piston for the No. 2 clutch

(24) Load piston for the No. 2 clutch

(25) Modulation reduction valve

(26) Modulation reduction valve for the No. 4 clutch

(27) Load piston for the No. 4 clutch

(28) Selector piston for the No. 4 clutch

(29) Selector piston for the No. 1 clutch

(30) Load piston for the No. 1 clutch

(31) Modulation reduction valve for the No. 1 clutch

(32) Modulation reduction valve for the No. 5 clutch

(33) Load piston for the No. 5 clutch

(34) Selector piston for the No. 5 clutch

(35) Selector piston for the No. 3 clutch

(36) Load piston for the No. 3 clutch

(37) Modulation reduction valve for the No. 3 clutch

(38) Modulation reduction valve for the No. 6 clutch

(39) Load piston for the No. 6 clutch

(40) Selector piston for the No. 6 clutch

(41) Selector piston for the dual stage relief valve

(42) Load piston for the dual stage relief valve

(43) Modulation reduction valve for the dual stage relief valve

(44) Pressure control valve

(A) Pressure tap for the No. 2 clutch

(B) Pressure tap for the No. 1 clutch

(C) Pressure tap for the No. 3 clutch

(D) Pressure tap of the dual stage relief valve for system pressure

(E) Pressure tap for the No. 4 clutch

(F) Pressure tap for the No. 5 clutch

(G) Pressure tap for the No. 6 clutch

(J) Pressure tap for upshift pressure

(K) Pressure tap for downshift pressure

(L) Pressure tap for charging pressure of the transmission

(M) Pressure tap for pilot oil of the transmission hydraulic control

Top view of oil lines for the transmission

(2) Transmission section of the hydraulic tank

(7) Transmission scavenge pump section

(8) Transmission lubrication section of the oil pump

(9) Transmission charging pump section

(11) Transmission lubrication hydraulic filter

(12) Transmission charging hydraulic filter

(17) Transmission oil cooler

(18) Transmission oil cooler inlet relief valve

(45) Transfer gears

(46) Transmission planetary

(47) Transmission hydraulic control

Side view of oil lines for the transmission

(2) Transmission section of the hydraulic tank

(7) Transmission scavenge pump section

(8) Transmission lubrication section of the oil pump

(9) Transmission charging pump section

(11) Transmission lubrication hydraulic filter

(12) Transmission charging hydraulic filter

(17) Transmission oil cooler

(18) Transmission oil cooler inlet relief valve

(19) Magnetic screen

(45) Transfer gears

(46) Transmission planetary

(47) Transmission hydraulic control

Side of transmission

(J) Pressure tap for upshift pressure

(K) Pressure tap for downshift pressure

Transmission hydraulic control

(21) Transmission lubrication relief valve

(A) Pressure tap for No. 2 clutch

(B) Pressure tap for No. 1 clutch

(C) Pressure tap for No. 3 clutch

(D) Pressure tap for the signal pressure of the dual stage relief valve in the selector and pressure control valve

(E) Pressure tap for No. 4 clutch

(F) Pressure tap for No. 5 clutch

(G) Pressure tap for No. 6 clutch

(H) This pressure tap is not used.

(L) Pressure tap for the pressure of the transmission charging pump section

Transfer gear case