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Massey Ferguson 5430,5435 PowerShuttle gearbox – Speedshift
The Speedshift unit is located between the Power Shuttle reverse clutch
and the mechanical unit comprising the driving gear. This is a
hydraulically controlled gear shift mechanism providing two input ratios
to the GBA20 gearbox. This function is provided by:
- a multidisc hydraulic clutch;
- an epicyclic gear train consisting of a planet carrier with three
double planet gears, an input sun gear and an output sun gear;
- a planet carrier hydraulic braking system.
The design of the Speedshift allows ratio shifting while driving without
declutching, even at full load.
Specific feature of the epicyclic gear train assembly
Legislation in force in certain countries limits forward speed to 30
kph. In this case, the sun gears (6) and (7) and planet gears (12) of
the Speedshift epicyclic gear train should be positioned as in figures.
MF 5430, 5435 Tractor Power Shuttle gearbox (Speedshift)
(1) Seals (2) Rivets (3) Screw (4) Ring (5) Secondary shaft (6) Input
sun gear (30 kph) Output sun gear (40 kph) (7) Input sun gear (40 kph)
Output sun gear (30 kph) (8) Planet gear pins (9) Planet carrier unit
(10) Friction washer (11) Rivet (12) Double planet gears (13) Housing
(14) Spacers (15) Hub (16) Needle roller bearing (17) Friction washers
(18) Spring washer (Belleville) (19) Ring restrictor (20) Thrust plate
(21) Brake disc (22) "O" ring (23) "O" ring (24) Screw (25) Hydraulic
cover plate (26) "O" ring (27) Front cover plate (28) Clutch piston (29)
"O" ring (30) Intermediate plates (31) Rings (32) Needle roller bearing
(33) Ring carrier (34) Screw (36) Primary shaft (37) Circlip (38) Tab
washer (39) Washer (40) Ball bearing (41) Screw (42) Discs (43) Spring
washers (48) Brake piston (50)
Planet carrier assembly
Mechanical action - boosting
In this position, the hydraulic components are not supplied and the
Speedshift operates in a mechanical manner. The oil in the chamber of
pistons (28) and (48)
returns to the housing via channel "C" and the solenoid valve mounted on
the MF 5435, 5430 Power Shuttle clutch unit. This clutch unit is located
on the front right-
hand side of the gearbox.
As the oil pressure has dropped, the planet carrier assembly (50) is
locked in rotation by the Belleville washer (18) which compresses the
thrust plate (20) and
immobilises the disc (21) splined with the planet carrier assembly.
Drive from the primary shaft (36) is transferred to the input sun gear
(7) splined to the shaft. The
sun gear (7) drives the double planet gears (12) idle-mounted on the
pins (8). The planet gears in turn drive the output sun gear (6) firmly
attached to the secondary
shaft (5), ratio 1.26.
Hydraulic action: direct drive reduction
The range shifting is carried out via a pulse button integrated into the
transmission lever handle. This button activates the solenoid valve
mounted on the Power
Shuttle clutch unit located on the front right-hand side of the GBA-20
gearbox.
The solenoid valve simultaneously supplies the chamber of pistons (48)
and (28). The brake piston (48) then presses against the thrust plate
(20) which
compresses the Belleville washer (18) thus releasing disc (21) and the
planet carrier assembly (50).
At the same time, the clutch piston (28) joins the intermediate plates
(30) and the discs (42) driven by the hub (15). As the intermediate
plates are firmly secured to
the planet carrier with three lugs, drive is transferred from the input
shaft (36) to the hub (15) and to the clutch assembly which drives the
planet carrier (50).
The
primary shaft (36), the planet carrier assembly and the sun gears turn
at the same speed as the secondary shaft (5), thus ensuring direct
drive, ratio 1.
Disconnect the Massey Ferguson 5435, 5430 tractor between the engine and
the gearbox. Drain the gearbox and the rear axle. Remove the spacer.
Remove the
Power Shuttle forward clutch. Remove the input unit. Separate the Power
Shuttle reverse clutch from the input unit. Position the unit
vertically.
Removing and disassembling the front cover plate
Removal
Remove the screws (24). Using two tabs or two makeshift rings, remove
the shaft (36), the ring carrier (33) and the front cover plate (27)
assembly.Recover and discard the seals (1). Remove and discard the seal rings
(31).
Disassembly
Remove the circlip (37). Remove the tab washer (38) and washer (39).
Separate the shaft (36) from the ring carrier (33).
If necessary, remove screws (34) (41). Separate and remove the ring
carrier (33) from the cover plate.
Remove the piston (48) by lightly tapping the cover plate with a wooden
block or using a jet of compressed air.
Remove the seals (22) and (23) and discard them.
The ring restrictor (19) is held in the cover plate by Loctite 648 or an
equivalent product.
The rivets (2) and (11) ensure oil channel tightness.
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