Low pressure hydraulic system for GBA20 and GBA25 gearboxes


Low pressure system hydraulic for GBA20 gearbox


Legend 
A Gearbox
B Centre housing
C Low pressure main supply (17 bar)
D Low pressure supply (17 bar) for Power Shuttle forward or reverse clutches
E Unit housing the control for the Power Shuttle and for the Dynashift
F Main accumulator
G Accumulator connected to the brake master cylinder hydraulic line
H Return - Power Shuttle forward and reverse clutches
I Supply - A/B clutch (forward travel) for Dynashift
J Non-return valve
K Filter

Low pressure (17 bar) Nitrogen
The supply line for the C/D clutch (reverse travel) for Dynashift is masked by the control unit. It is located between the latter and the gearbox.

Specifications of accumulators F and G
Accumulator F assists the low-pressure hydraulic line. Accumulator G maintains the brake master cylinder hydraulic line under pneumatic pressure as soon as the tractor stops (ignition switched off).
These two accumulators have the same specifications:
- Brand: HYDAC
- Type: 1/20
- Capacity: 1 l
- Gas: Nitrogen
- Inflation pressure: 8 to 10 bar
The pressure should be checked every six months, with the engine stopped.

Low pressure hydraulic system for GBA25 gearbox (40 kph version)


Legend (Fig. 24, Fig. 25)
A Gearbox/Powershift module assembly
B Centre housing
C Low pressure main supply (21 bar)
E Unit housing the control:
- for the Power Shuttle
- for the Dynashift module
- for the multiplier module
F Main accumulator
G Accumulator connected to the brake master cylinder hydraulic line
K Filter
L Low pressure supply (21 bar) for the Powershift module and the Power Shuttle
M Low pressure supply (21 bar) for range solenoid valves on gearbox type GBA25
N Range 1 and 2 solenoid valves
O Range 3 and 4 solenoid valves


Specifications of accumulators F and G
Accumulator F assists the low-pressure hydraulic line. Accumulator G maintains the brake master cylinder hydraulic line under pneumatic pressure as soon as the tractor stops (ignition switched off).
These two accumulators have the same specifications:
- Brand: HYDAC
- Type: 1/20
- Capacity: 1
- Gas: Nitrogen
- Inflation pressure: 8 to 10 bar
The pressure should be checked every six months, with the engine stopped.

Low pressure system for gearbox type GBA25 with high pressure braking unit


Legend (Fig. 26)
A Gearbox/Powershift module assembly
B Centre housing
C Low pressure main supply (21 bar)
E Unit housing the control:
- for the Power Shuttle
- for the Dynashift module
- for the multiplier module
F Main accumulator
K Filter
L Low pressure supply (21 bar) for the Powershift module and the Power Shuttle
N Range 1 and 2 solenoid valves
O Range 3 and 4 solenoid valves
P High-pressure braking unit
Q Accumulator

Specifications of accumulators F and Q
• Main low pressure accumulator F
- Brand: HYDAC
- Type: 1/20
- Capacity: 1
- Gas: Nitrogen
- Inflation pressure: 8 to 10 bar
• Accumulator Q for high-pressure braking unit
- Brand: HYDAC
- Type: SBO210
- Capacity: 1.4 l
- Gas: Nitrogen
- Inflation pressure: 53 to 56 bar.

Thermo valve



Legend 

(1) Thermo valve
E Lubrication system oil inlet
R Routing of oil to the cooler
S Oil outlet to hydraulic components for lubrication

1.Routing of oil being heated (E to S)
2.Routing of hot oil (E to R)