Toro Groundsmaster 7200 Service Manual page 63

The Charge Relief Valve Pressure Test should be per-
formed if a traction circuit problem is identified. This test
will determine if the transmission charge relief valve is
operating correctly.
Procedure for Charge Relief Valve Pressure Test:
1. Make sure hydraulic oil is at normal operating tem-
perature.
2. Make sure that traction drive is correctly adjusted for
the neutral position.
WARNING
Before disconnecting or performing any work on
the hydraulic system, all pressure in the system
must be relieved. See Relieving Hydraulic System
Pressure in the General Information section.
3. Park machine on a level surface with the cutting deck
(or implement) lowered and off. Apply parking brake.
Make sure engine is off.
4. Read Precautions for Hydraulic Testing listed at the
beginning of this section.
5. Thoroughly clean transmission area surrounding
charge pressure test port on right side of transmission
(Fig. 15).
6. Remove plug from charge pressure test port (Fig.
15). Connect hydraulic pressure gauge (1000 PSI / 70
bar) with an attached hydraulic hose to the transmission
charge pressure port.
7. Make sure that traction levers are in the neutral
locked position and that the parking brake is applied.
8. Start engine and run at low idle speed (1500 to 1650
RPM). Check for any hydraulic leakage from test con-
nections and correct before proceeding with test.
9. With engine running, move throttle to full speed
(3200 RPM).
10.Pressure gauge should read from 70 to 100 PSI (4.8
to 6.9 bar). Record test result.
11. If charge relief pressure specification is not met,
consider the following:
A. The transmission charge relief valve is faulty. Re-
pair or replace the charge relief valve (see Transmis-
sion Service in the Service and Repairs section).
B. A transmission traction relief valve or flushing
valve is leaking or damaged (see Transmission Ser-
vice in the Service and Repairs section).
Groundsmaster 7200/7210
C. The charge pump in the transmission is faulty
(PTO operation would also be affected. See Trans-
mission Service in the Service and Repairs section).
12.A dynamic charge pressure test can be performed as
follows:
A. With hydraulic pressure gauge still connected, sit
in the operator seat and move the traction levers to
forward.
B. While machine is moving, monitor the charge
pressure reading on the pressure gauge.
C. The charge pressure should drop no more than
15% from initial test reading (Step 10 above) as the
machine is moving (e.g. if initial charge pressure was
100 PSI (6.9 bar), charge pressure while machine is
moving should be above 85 PSI (5.9 bar)).
D. A pressure drop of more than 15% indicates a
traction circuit leak (e.g. a leaking transmission
check valve, a worn/damaged transmission piston
pump). If charge pressure is good under no load, but
drops below specification when under traction load,
the transmission piston pump(s) should be sus-
pected of wear or damage. When a pump is worn or
damaged, the charge pump is not able to keep up
with internal leakage in the traction circuit.
13.Stop machine and shut off engine.
14.Relieve hydraulic system pressure (see Relieving
Hydraulic System Pressure in the General Information
section). Remove pressure gauge from transmission
charge pressure test port. Install plug into port and
torque plug from 13 to 15 ft–lb (17.7 to 21.5 N–m).
Charge Pressure
Page 4 – 27
FRONT
Test Port
Figure 15
Hydraulic System