Layout of the main components with diagrams of the low and high pressure hydraulic systems


Tractors equipped transmission with GBA20 gearbox


Parts list 
(1) To front differential lock (2) Steering ram (3) Steering spool valve (Orbitrol) (4) Forward clutch (Power Shuttle) (5) Reverse clutch (Power Shuttle) (6) Dynashift (7) 1.5 bar valve (8) Hare/Tortoise mechanism
(9) To power take-off clutch (10) Suction strainer (250 μ) (11) Left-hand hydraulic cover plate (12) Charge pump (13) 150 μ suction strainer (14) Charge pump hydraulic manifold (15) 4WD clutch (16) Trumpet housing lubrication (17) To rear differential lock (18) Lift rams (19) Auxiliary spool valves (20) PTO brake (21) Cooler (22) To brake master cylinders (25) Pressure connector (charge) (26) Proportional solenoid valves (27) Hydraulic control unit (Power Shuttle and Dynashift) (28) Dynashift solenoid valve - Clutch A/B (29) Dynashift solenoid valve - Clutch C/D (30) Accumulator (31) 60 μ filter (32) Hare/Tortoise solenoid valve (33) Differential lock solenoid valve (34) PTO proportional solenoid valve (35) PTO brake solenoid valve (36) 4WD solenoid valve (if fitted) (37) Main filter (15 μ(38) Blockage indicator (39) Pump regulator (40) Low-pressure spool (41) High-pressure spool
(42) Trailer brake valve (if fitted) (43) Priority block without trailer braking (44) Priority block with trailer braking (45) Right-hand hydraulic cover plate (46) 22 bar safety valve (47) Low pressure switch
(48) Lubrication switch (49) Variable displacement pump (50) 5 bar safety valve (51) Pressure relief valve (52) Left and right brakes (53) Trailer brake connector (54) Linkage spool valve (55) Braking assistance accumulator (56) Mechanically operated auxiliary spool valves (57) Hydraulic unit (suspended front axle) (58) FTE valve (67) 13 bar valve (68) Steering priority spool
(69) Cooling system with thermo valve (if fitted)

Legend
Red - High pressure
Dark Green - Low pressure
Blue - Lubrication
Dark blue - Suction
Green - Return
Yellow - Brake cone
Brown - Control
Pink - Charge
Striped - Re-supply to variable displacement pump (slave devices not used).


Tractors equipped with trailer brake mechanism
Tractors not equipped with trailer brake mechanism

F1 Action on left-hand brake
F2 Action on right-hand brake
F3 Pedals locked together for tractor and trailer braking (if trailer hitched): action on F1 and F2 at the same time
H Lubrication of the mechanical components of the rear PTO
H1 PTO clutch lubrication
I Trumpet housing lubrication
J Gearbox lubrication
K Lubrication of the pinion rear bearing
L Lubrication of the Power Shuttle

Tractors equipped transmission with GBA25 gearbox (40 kph)


Parts list 
(1) To front differential lock (2) Steering ram (3) Steering spool valve (Orbitrol) (4) Power Shuttle (forward clutch) (5) Power Shuttle (reverse clutch) (6) Powershift module (9) To power take-off clutch (11) Left-hand hydraulic cover plate (12) Charge pump (13) 150 μ suction strainer (14) Charge pump hydraulic manifold (15) 4WD clutch (16) Trumpet housing lubrication (17) To rear differential lock (18) Lift rams (19) Auxiliary spool valves (20) PTO brake (21) Oil cooler (22) To brake master cylinders
(23) EV1 solenoid valve (L52) (24) EV2 solenoid valve (L53) (25) EV3 solenoid valve (L54) (26) EV4 solenoid valve (L55) (30) Accumulator (31) 60 μ filter (33) Differential lock solenoid valve (34) PTO proportional solenoid valve (35) PTO brake solenoid valve (36) 4WD solenoid valve (if fitted)
(37) Main filter (15 μ) (38) Blockage indicator (39) Pump regulator (40) Low-pressure spool (41) High-pressure spool (42) Trailer brake valve (if fitted) (43) Priority block without trailer braking (44) Priority block with trailer braking (45) Right-hand hydraulic cover plate (46) 24 bar safety valve (47) Low pressure switch (48) Lubrication switch (49) Variable displacement pump
(50) 5 bar safety valve (51) Pressure relief valve (52) Left and right brakes (53) Trailer brake connector (54) Linkage spool valve (55) Braking assistance accumulator (56) Mechanically operated auxiliary spool valves (57) Suspended front axle hydraulic unit (if fitted) (58) FTE valve (68) Steering priority spool
(69) Cooling system with thermo valve (70) Cooling system without thermo valve (72) Hoses to suspension ram small and large hydraulic chambers (73) Lock or suspension solenoid valve (74) Lifting and lowering solenoid valves (75) Suspension ram with two hydraulic chambers
(76) Accumulator (210 bar) (77) Proportional solenoid valves for Dynashift and multiplier modules (78) Parker valve (79) Power Shuttle and Powershift module hydraulic control unit (80) Power Shuttle proportional solenoid valves (81) Hydraulic pressure connectors for multiplier module and Power Shuttle (83) Limit switch (ranges 1 to 4)


Tractors equipped with trailer brake mechanism
Tractors not equipped with trailer brake mechanism

F1 Action on left-hand brake
F2 Action on right-hand brake
F3 Pedals locked together for tractor and trailer
braking (if trailer hitched): action on F1 and F2 at the same time
H Lubrication of the mechanical components of the PTO
I Trumpet housing lubrication
J Gearbox lubrication
J1 Powershift module lubrication
K Lubrication of the pinion rear bearing

Tractors equipped transmission with GBA25 gearbox and high pressure (HP) braking


Parts list 
(1) To front differential lock (2) Steering ram (3) Steering spool valve (Orbitrol) (4) Power Shuttle (forward clutch) (5) Power Shuttle (reverse clutch) (6) Powershift module (9) To power take-off clutch
(11) Left-hand hydraulic cover plate (12) Charge pump (13) 150 μ suction strainer (14) Charge pump hydraulic manifold (15) 4WD clutch (16) Trumpet housing lubrication (17) To rear differential lock (18) Lift rams (19) Auxiliary spool valves (20) PTO brake (21) Oil cooler (23) EV1 solenoid valve (L52) (24) EV2 solenoid valve (L53) (25) EV3 solenoid valve (L54) (26) EV4 solenoid valve (L55) (30) Accumulator (31) 60 μ filter (33) Differential lock solenoid valve (34) PTO proportional solenoid valve (35) PTO brake solenoid valve (36) 4WD solenoid valve (if fitted) (37) Main filter (15 μ) (38) Blockage indicator (39) Pump regulator (40) Low-pressure spool (41) High-pressure spool (42) Trailer brake valve (if fitted) (43) Priority block without trailer braking
(44) Priority block with trailer braking (45) Right-hand hydraulic cover plate (46) 24 bar safety valve (47) Low pressure switch (48) Lubrication switch (49) Variable displacement pump (50) 5 bar safety valve (51) Pressure relief valve (52) Left and right brakes (53) Trailer brake connector (54) Linkage spool valve (56) Mechanically operated auxiliary spool valves (57) Suspended front axle hydraulic unit (if fitted) (68) Steering priority spool (69) Cooling system with thermo valve (70) Cooling system without thermo valve (72) Hoses to suspension ram small and large hydraulic chambers (73) Lock or suspension solenoid valve (74) Lifting and lowering solenoid valves
(75) Suspension ram with two hydraulic chambers (76) Accumulator (210 bar)
(77) Proportional solenoid valves for Dynashift and multiplier modules (78) Parker valve (79) Power Shuttle and Powershift module hydraulic control unit (80) Power Shuttle proportional solenoid valves (81) Hydraulic pressure connectors for multiplier module and Power Shuttle (83) Limit switch (ranges 1 to 4) (85) High pressure brake valves/unit assembly (87) Accumulator (210 bar) (88) Non-return valve (89) Drain screw (90) Pressure relief valve (91) Filter (25 μ(92) High-pressure braking unit (93) Solenoid valve (0/12 volts)


Tractors equipped with trailer brake mechanism
On tractors not fitted with the trailer brake mechanism, the pipes (T) and the connector (53) are not fitted.

F1 Action on left-hand brake
F2 Action on right-hand brake
F3 Pedals locked together for tractor and trailer braking (if trailer hitched): action on F1 and F2 at the same time
H Lubrication of the mechanical components of the PTO
I Trumpet housing lubrication
J Gearbox lubrication
J1 Powershift module lubrication
K Lubrication of the pinion rear bearing
The letters B, J, O R and V correspond to the colour marks (rings) used to identify the hydraulic pipes located to the right of the cab and their routing between the cab and the transmission.