TRANSMISSION HYDRAULIC CONTROLS
a restriction to the P2 oil flow around the piston
(4). This restriction causes a decrease in pressure of
the P2 oil to the direction clutches.
P 2 p r e s s u r e c a n b e c o n t r o l l e d f r o m
approximately 9 to 150 psi (60 to 1030 kPa) by the
manual modulation valve. Because the direction
clutches are not fully engaged, the operator can
slip the clutch (make the discs slide in relation to
the plates) and move the machine a little distance
at a time.
When the operator lets the pedal come hack up,
spool (6) moves back in and the P1 and P2
pressures increase to their maximum pressures. The
modulating reducing valve (9) gives modulation to
the pressure oil and lets the clutches engage