Toro Groundsmaster 360 Service Manual page 74

Forward Direction (continued)
Reverse Direction
Hydraulic System: Hydraulic Flow Diagrams
In the forward direction, pilot directional valves PD1 and PD2 in the traction
manifold assembly are shifted. These shifted valves along with the check valves
(CV1 and CV2) help to provide fluid where needed in the traction circuits for
optimal traction operation when turning.
The 2 transmission traction circuits include flushing valves (one for each traction
circuit) in the piston pump that bleed off a small amount of hydraulic fluid for
cooling of the closed loop traction circuits. The flushing valves are opened only
during forward direction operation. When the flushing valves are unseated, some
fluid from the low-pressure side of the traction loop is returned to the hydraulic
tank. The fluid loss from the closed loops through the flushing valves is replaced
by the charge pump.
The traction manifold assembly includes a bi-directional relief valve (CRV) and
orifice fittings to prevent pressure differences in the 2 circuits reducing tire
scuffing when turning.
To provide 4-wheel dynamic braking when the traction pedal is released, the
pilot directional valves PD1 and PD2 in the traction manifold assembly shift to
their normally closed position. This disables the check valves (CV1 and CV2)
ensuring 4-wheel hydrostatic braking.
g036058
1. Port A
2. Port B
3. Port C
The traction circuit operates essentially the same in reverse as it does in the
forward direction.
When a traction pedal is pushed for reverse, the linkage connected to the
pedal positions the swash plates in both transmission-piston pumps to provide
hydraulic fluid flow from the transmission (port B and D). This fluid flows to the
front wheel motors and then on to the rear wheel motors turning the motors in
the reverse direction. The fluid flow from the rear wheel motors return to the
transmission (port A and port C) and is continuously pumped while the traction
pedal is pushed for reverse.
In the reverse direction, transmission pump flow is routed to a front wheel motor
and then to the opposite rear wheel motor (e.g., the right front and then to the left
rear). The reverse traction circuit relief valve setting is 27,600 kPa (4,000 psi).
Figure 26
4. Port D
5. Balancing hose
Page 4–16 Groundsmaster 360
16225SL Rev C