RENR6506-00
30Page,B/W,D.G.M.
©2003 Caterpillar
All Rights Reserved
Printed in U.S.A.
RENR6506-00July 2003
773 and 775E Off-Highway TruckHydraulic System
BDA259-UPBEC202-UP
ONE POSITION TWO POSITION THREE POSITION
VENTED PRESSURIZED RETURN ABOVE FLUID LEVEL RETURN BELOW FLUID LEVEL
LINES CROSSING LINES JOINING
TWO-WAY THREE-WAY FOUR-WAY
SPRING CONTROL VALVES RESTRICTION LINE RESTRICTION
(FIXED)
2-SECTION PUMP
MAIN AUX.
SPRING
(ADJUSTABLE)
VARIABLILTY LINE RESTRICTION
(VARIABLE)
LINE RESTRICTION(VARIABLE and PRESSURE COMPENSATED)
PRESSURE
COMPENSATION
PUMP: VARIABLE andPRESSURE COMPENSATED
ENERGY TRIANGLES
HYDRAULIC PNEUMATIC
MEASUREMENT
PRESSURE TEMPERATURE FLOW
ROTATING SHAFTS
UNIDIRECTIONAL BIDIRECTIONAL
PUSH-PULL LEVER PEDALGENERAL MANUAL PUSH BUTTON SPRING
MANUAL CONTROL SYMBOLS
HYDRAULIC MOTORS
FIXED
DISPLACEMENT
VARIABLE DISPLACEMENT
NON-COMPENSATED
UNIDIRECTIONAL
BIDIRECTIONAL
HYDRAULIC PUMPS
FLUID STORAGE RESERVOIRS
CROSSING AND JOINING LINES
VALVE ENVELOPES VALVE PORTS
BASIC COMPONENT SYMBOLS
FLUID CONDITIONERPUMP or MOTOR
FLUID POWER SYMBOLS
FIXED
DISPLACEMENT
VARIABLE DISPLACEMENT
NON-COMPENSATED
UNIDIRECTIONAL
BIDIRECTIONAL
VALVES
PILOT CONTROL SYMBOLSRELEASED PRESSURE
EXTERNAL RETURN INTERNAL RETURN
REMOTE SUPPLY PRESSURE
SIMPLIFIED COMPLETE INTERNAL
SUPPLY PRESSURE
ACCUMULATORS
SPRING LOADED GAS CHARGED
SOLENOIDor MANUAL
SOLENOIDand PILOT
SOLENOID andPILOT or MANUAL
COMBINATION CONTROLS
SOLENOID SERVO THERMAL DETENT
HYDRAULIC AND PNEUMATIC CYLINDERS
DOUBLE ACTINGSINGLE ACTING
BASIC SYMBOL SPRING LOADED
CHECK VALVES
TWO
POSITION
INFINITE
POSITIONING
FLOW IN ONE
DIRECTION
FLOW ALLOWED IN
EITHER DIRECTION
THREE
POSITION
CROSS
FLOWPARALLEL
FLOW
INTERNAL PASSAGEWAYS
NORMAL POSITION
A B
P T
A B
P T
SHIFTED POSITION INFINITE POSITION
CONTROL VALVES
Hoist Control Valve Main Pump
Steering Check and Relief Valve (43)
52G704-YLE790-PK 11
43
1015
704-GY922-BR
703-BU922-BR
G705-GNE790-PK
54
Pump and Motor for the Secondary Steering, Brake Release,Prelubrication, and QuickEvac
Transmission Hydraulic Control (58) Transmission Rear View
22 3123
UpshiftSolenoid
705-PK922-BR
Lockup ClutchSolenoid
DownshiftSolenoid
Traction Control Valve
Parking and Secondary Brake Valve (47)
Diverter Valve (Towing) (40)
Selector Solenoid(4 Way)
40
47
774-YLK952-BR775-BRK952-BR
773-GYK952-BR
ProportionalSolenoidValve
ItemPart
NumberDescription
Schematic
LocationItem
Part
NumberDescription
Schematic
Location
1 2A-7070 Service and Parking Brake (Rear)F-3, I-3
D-12 , I-1232 138-4733
Check Valve
(Parking Brake Release)H-10 / H-2
2 9C-4937Air Breather
(Torque Converter and Transmission)B-10 33 123-5150 Check Valve B-7
3 145-5155 Hoist Cylinder D-8 35 104-1817 Oil Cooler (Power Train) C-12
4 8X-3572 Plate (Orifice) D-8 36 9T-5665 Hydraulic Filter (Steering) G-3
5 8P-3795 Screen A-11 37 8X-6987 Air/Hydraulic Cylinder (Front Brake) H-7
6 9P-0673 Relief Valve (Torque Converter Inlet) A-10 38 170-8018 Hydraulic Tank (Steering) B-3
7 111-6841 Transmission Charging Pump Section A-12 39 9T-0818 Steering Pump Case Drain Filter B-3
8 111-6841 Transmission Scavenge Pump Section A-12 40 3G-2887 Diverter Valve (Towing) G-10
9 8P-3795 Screen A-13 41 8X-4575 Air Breather (Hoist and Brake) E-9
10 111-8399 Brake Pump Section G-8 / H-1 42 9P-0673 Air/Hydraulic Cylinder (Rear Brake) G-12
11 111-8399 Hoist Pump Section G-8 43 Check and Relief Valve (Steering) D-2
12 105-3357 Steering Cylinder F-2 44Relief Valve
(Primary Steering Backup)D-2
13 8W-7374 Hydraulic Caliper Service Brake (Front) F-5 / H-5 45Relief Valve
(Secondary Steering Backup)D-2
14 192-4286 Metering Pump (Steering) E-2 46 Pressure Reducing Valve (Steering) D-3
15 219-1964 Piston Pump (Steering) G-8 / C-2 47 113-1543 Brake Valve (Parking and Secondary) H-10
16 219-1964 Pressure Compensator Valve C-2 48 153-2739 Hydraulic Tank (Hoist and Brake) D-9 / D-10
17 212-0394Lockup Clutch and Solenoid Valve
(Torque Converter)B-12 49 9T-9227 Screen D-9
18 132-5447 Hydraulic Filter (Power Train) B-11 50 7J-3723 Screen D-9
19 132-5448 Hydraulic Filter (Parking Brake Release) G-8 / H-2 51 Control Valve (Hoist) E-6
20 8J-6875 Shuttle Valve (Resolver Valve – Steering) D-2 52Proportional Solenoid
(Hoist – Raise)E-7
21 9Y-1911 Oil Filter (Engine) B-8 53 Relief Valve (Brake Oil Cooler) E-7
22Brake Release Section of the Electric
Drive Pump54
Proportional Solenoid
(Hoist – Lower)F-7
23Secondary Steering Section of the
Electric Drive Pump55 143-9426 Makeup Tank (Brake) I-11
24 Load Sensing Valve 56 3E-6450 Pressure Switch (Steering Pump Oil) D-3
25 Relief Valve (Secondary Steering – Main) 57 Torque Converter Housing A-13
26 2G-6535 Slack Adjuster (Rear) F-12 / G-3 58 Transmission Hydraulic Control B-11
27 8P-1471 Relief Valve (Torque Converter Outlet) C-13 59 Transmission Housing A-11
28 9G-9208 Traction Control Valve G-1 60 200-5375Power Train Electronic Control Module
(ECM)C-1
29 141-4109 Oil Cooler (Rear Brake) F-11 61 212-0394 Relief Vavle (Vacum Breaker) C-1
30 6E-6640 Screen F-10 62 9X-4455 Pressure Switch Assembly C2
31 209-3406Prelubrication and QuickEvac Section of
the Electric Drive PumpB-6 / G-10
(*) 773E Only
(**) 775E Only
212-0394
D-2
B-7
G-10
D-2
Component Locations
*194-1465
**175-7852
175-7050
175-7051
209-3406
14
26
Hoist and Brake Hydraulic Tank
Steering Hydraulic Tank
Slack Adjuster Rear Brake (26)
Steering Metering Pump (14)
13 12 14 3 3247484950515253
LL
404137
3839
43444546
56 54
5542
KK
14
2930
33
35
DD
20
27GG
34
36
2324
2531
62
21PP
4 3567891011AA1213 151617BB18CC
19
12
2626
28
FF
HH
JJ
EE
58 RR
22
2832 4152 48 4734 36 53 544237
38 39
5146 162 101145 56 1555
4443
14
20
21
60
30
29
19
1 2658 59408 509 24 344957172712131822
Machine Component and Tap Locations
765
62
61
59
MM NN
24
QQ 60
61
57
35 33 23
3125
Tap
NumberDescription
Schematic
Location
AA Pressure Tap (Hoist) G-8
BB Pressure Tap (Lockup Clutch Maximum Pressure) B-12
CC Sampling Valve (Torque Converter Pressure) C-11
DD Oil Sampling Valve (Brake) G-8 / H-2
EE Pressure Tap (Transmission Lubrication Pressure) B-10
FF Pressure Tap (Rear Brake Service) F-12
GG Pressure Tap (Torque Converter Pressure) C-13
HH Pressure Tap (Parking Brake) D-12
JJ Pressure Tap (Brake Cooling) D-11
KK Pressure Tap (Steering) E-2
LL Sampling Valve (Steering Oil) B-3
MM Pressure Tap (Hoist Cylinder - Head End) D-8
NN Pressure Tap (Hoist Cylinder - Head End) D-8
PP Scheduled Oil Sampling Valve (Engine Oil) G-9
QQ Pressure Tap (Front Brake) L-7
RR Pressure Tap (Transmission Control) W-7
Tap Locations
Pressure, Sampling, and Sensor
Description Media Number
Specifications RENR6507
Systems Operation RENR6508
Testing and Adjusting RENR6509
Disassembly and Assembly SENR1574
Specifications: (Hydraulic System) RENR6515
Testing & Adjusting: (Hydraulic System) RENR6516
Specifications: (Steering System) RENR6510
Testing & Adjusting: (Steering System) RENR6511
Specifications: (Air System & Brakes) RENR6512
Testing & Adjusting: (Air System & Brakes) RENR6513
Specifications, Systems Operation, Testing &
Adjusting: (Oil Evacuation System)RENR3391
Specifications, Systems Operation, Testing &
Adjusting: (Suspension Cylinder)RENR6514
Schematic: (Electrical System) RENR6518
Automatic Electronic Traction Aid (AETA) SENR2986
Additional Manuals
Related Manuals
Power Train
Machine System
Electrical System
RR FF
LL
PP
KK
CC GG BBQQ
RENR6506-00
30Page,Color2,DGM
A
B
C
D
E
F
G
H
I
123456789101112
123456789101112
A
B
C
D
E
F
G
H
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13
13
HYDRAULIC CIRCUIT COLOR DESCRIPTIONSPump Output(Brake)(Hoist)(Steering).
Pump Output(Brake Release)(Secondary Steering)(Prelube and Quickevac).
Pump Output(Transmission).
Supply Line.Drain/Return Line.Brake Circuit.Engine Prelube and Quickevac Circuit.Steering Circuit.Torque Converter/Transmission Circuit.Hoist Circuit.Traction Control Circuit.
M
12
14
1615
46
KK 20
24
43 44
4525
36
38
39
56
60
61
LL
23
22
31
CC
5
6
17
18
2
7
8
9
BB
27
35
GGEE
58
57
59
M
1
1
4
3
13
13
AA
10
11
15 19
47
32
26
29 30
50
48
49
53
52
51
22
40
FF
41
JJ
HH
37
DD
NNMM
54
55
23
31
42
32
47
1
26
1
10
28
19
Selector(4 Way)Solenoid
ProportionalSolenoid
DD
33
31
2322
21
M
Engine Prelubrication and Quickevac
Traction Control System
Steering Hydraulic System
Torque Converter and Transmission Hydraulic System
62
ECM
Main
LINEAR PATTERNS
Drain / Return Lines
Components
Pilot/Load Sensing Pressure
Pressure Line
THIS SCHEMATIC IS FOR THE 773E and 775E OFF HIGHWAY TRUCK
Components are shown installed on a fully operable machine with the key and engine
off and transmission shifter in neutral.