Raise Cutting Unit - Toro Groundsmaster
4000?D Service Manual

PRELIMINARY – For Toro Distributor and Toro Company use only.

Raise Cutting Unit

A four section gear pump is coupled to the piston (trac-
tion) pump. The third gear pump section supplies hy-
draulic flow to the lift/lower control valve and the steering
control valve. Hydraulic flow from this pump section is
delivered to the two circuits through a proportional flow
divider. The gear pump takes its suction from the hy-
draulic reservoir.
When the cutting units are in a stationary position, flow
from the gear pump is by−passed through the lift/lower
control valve, counterbalance manifold, oil filter and
traction charge circuit.
To raise a side cutting unit, the appropriate lift lever on
the lift/lower control valve is pulled to allow valve shift in
the lift/lower control. This valve change allows hydraulic
pressure to the piston end of the lift cylinder and causes
the shaft to extend, raising the cutting unit. Oil from the
rod end of the cylinder flows to the traction charge cir-
cuit. When the lift lever is released, the lift cylinder is held
in position.
Hydraulic System
To raise the front cutting unit, the center lift lever on the
lift/lower control valve is pulled to allow valve shift in the
lift/lower control. This valve change allows hydraulic
pressure to the rod end of the front deck lift cylinders,
causing the cylinders to retract. As the cylinders retract,
the front deck raises. Oil from the piston end of the cylin-
der returns to the hydraulic reservoir. When the lift lever
is released, the lift cylinder is held in position.
An adjustable counterbalance valve maintains back
pressure on the lift cylinders. A relief valve located in the
lift/lower control valve limits circuit pressure. Excess cir-
cuit flow is routed to the oil filter and then to the traction
charge circuit.
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