MASSEY FERGUSON 5400 - General

Massey Ferguson 5400 - Issue 1.a
05A02.3
General - GBA20 with Power Shuttle Operation
A . General
The housing of the GBA20 gearbox with Power Shuttle
consists of the following main components, in the
order given:
- the Power Shuttle,
- the Speedshift input unit,
- the input gear train,
- the main gearbox,
- the creeper or super creeper gearbox (option).
Only the gearbox is described in this section.
A broad description is given of the major components
because specific and detailed descriptions can be seen
in the sections provided for each component.
Power Shuttle
The Power Shuttle consists of two oil bath multidisc
clutches (one for forward operation and one for
reverse operation). These clutches are located to the
front of the input unit, in front of the Speedshift unit.
The Power Shuttle is controlled by two proportional
solenoid valves operated by a lever located to the left
under the steering wheel and managed by the tractor
electronic system.
Speedshift input unit
The Speedshift input unit consists of a hydraulic mech-
anism and an epicyclic gear train. It is located to the
rear of the Power Shuttle. It allows to obtain two
gearbox input ratios via a hydraulic control unit and a
solenoid valve.
Gearbox input gear train
The gearbox input gear train consists of two meshed
pinions:
- a driving pinion located at the rear of the input unit,
- a driven pinion integral with the gearbox mainshaft.
The input gear train transmits drive from the engine to
the gearbox.
Main gearbox
The main gearbox consists of four basic gears and two
speed ranges (Hare and Tortoise), giving a total of eight
gear ratios for each direction of travel.
This transmission covers all usage requirements.
Creeper unit (option)
The creeper unit is fitted to the gearbox output shaft.
It allows slow travel. It operates at a ratio of 4/1.
It is controlled mechanically and should only be
engaged when the gearbox is in Tortoise range.
Super creeper unit (option)
The super creeper unit is also fitted to the gearbox
output shaft.
It consists of two epicyclic gear trains which allow to
obtain a reduction ration of 14/1 and therefore allows
very slow travel.
Like the creeper unit, it is controlled mechanically.