Traction Circuit - Toro Reelmaster 2000-D Service Manual

Traction Circuit

Forward Direction
The traction pump is driven by the engine through the
pulleys and pump drive belt. The traction circuit of the
hydraulic system acts essentially as a closed loop. Tak-
ing its suction directly from the return side of the wheel
motors of the traction circuit, the traction pump supplies
oil flow to the wheel motors through the supply side of
the traction circuit.
With the engine running and the traction pedal in the
neutral position, the traction pump supplies no flow to
the wheel motors. When the traction pedal is pressed to
the forward position, the linkage from the pedal posi-
tions the swash plate in the traction pump so oil flows out
the top port of the pump. Oil flow out of the top port goes
to the wheel motors and turns them in the forward direc-
tion.
Oil flowing out of the wheel motors returns to the bottom
port of the traction pump and is continuously pumped
out the top port.
A small amount of hydraulic oil leaves the traction circuit
through the bi–directional shuttle valve in the front left
wheel motor. This oil is cooled as it flows through the oil
cooler and returns to the reservoir.
Filtered hydraulic oil is supplied to the traction circuit
from the charge pump, through the lift control valve, and
back through the charge circuit check valves. This fil-
tered oil replaces oil losses from flow through the shuttle
valve and small amounts of pump and motor leakage.
The charge pump and shuttle valve circuits allow for in-
direct cooling and filtering of the traction circuit.
If the optional 3 Wheel Drive Kit has been installed, the
3WD selector valve allows forward flow to the rear wheel
only when the Reel Engagement switch is in the ON
position. When the reels are switched on, the solenoid
in the 3WD selector valve is energized and shifted, di-
recting hydraulic flow to the rear wheel motor.
Reelmaster 2000–D
Reverse Direction
The traction circuit operates essentially the same in re-
verse as it does in the forward direction. However, the
flow through the circuit is reversed. When the traction
pedal is pressed to the reverse position, the linkage from
the pedal positions the swash plate in the traction motor
so oil flows out the bottom port of the pump. Oil flow out
of the bottom port goes to the wheel motors and turns
them in the reverse direction.
Oil flowing out of the wheel motors returns to the top port
of the traction pump and is continuously pumped out the
bottom port.
The charge and shuttle valve circuits function the same
in reverse as they did in the forward direction.
If the optional 3 Wheel Drive Kit has been installed, the
pilot directional valve in the 3WD selector valve pre-
vents reverse flow to the rear wheel. As a result, there
is no 3WD in reverse.
Page 4 – 9 Hydraulic System