Case 580SR Service Manual page 179

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SECTION 21 - TRANSMISSION 113
THE INPUT OR DIRECTIONAL CLUTCHES
The turbine shaft driven from the turbine transmits
power to the forward or reverse clutches.
These clutches consists of a drum with splines and
a bore to receive a hydraulic actuated piston.
The piston is oil tight by the use of sealing rings.
A steel disc with external splines is inserted into the
drum and rests against the piston.
Next, a friction disc with splines at the inner diameter
is inserted.
Discs are alternated until the required total is
achieved.
A back up plate is then inserted and secured with a
snap ring.
A hub with outer diameter splines is inserted into the
splines of discs with teeth on the inner diameter.
The discs and hub are free to increase in speed or
rotate in the opposite direction as long as no pres-
sure is present in that specific clutch.
To engage the clutch, the control valve which is fitted
on the side of the transmission will direct oil under
F27725
pressure through tubes and passages to the select-
The input or directional clutches
ed clutch shafts.
Oil seals are located on the clutch shafts.
These rings direct the oil through a drilled passage
in the shaft to the desired clutch.
Pressure of the oil forces the piston and discs
against the back up plate.
The discs with splines on the outer diameter clamp-
ing against discs with teeth on the inner diameter en-
ables the drum and hub to be locked together and
allows them to drive as one unit.
When the clutch is released, a return spring will push
the piston back and oil will drain back via the control
valve into the transmission sump.
The T16000 transmission has one reverse clutch
and two forward clutches (forward low and forward
high).
This in combination with the two range clutches re-
sult in the transmission having 4 forward speeds and
2 reverse speeds.
The engagement of the directional clutches is modu-
lated; which means that clutch pressure is built up
gradually.
This will enable the unit to make forward, reverse
shifts while the vehicle is still moving and will allow
smooth engagement of drive.
The modulation is controlled electronically in the
control valve.