Service Manual

Groundsmaster 7200/7210 Hydraulic SystemPage 4 – 31
The Traction Relief Valve Pressure Test should be per-
formed if a traction circuit problem is identified. This test
will determine if a transmission relief valve is operating
correctly.
Procedure for Traction Relief Valve Pressure
Test:
1. Make sure hydraulic oil is at normal operating tem-
perature. Also, 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.
2. Park machine on a level surface with the cutting deck
(or implement) lowered and off. Make sure engine is off
and that the parking brake is not applied.
3. Read Precautions for Hydraulic Testing listed at the
beginning of this section.
4. Thoroughly clean transmission area surrounding
traction circuit hoses on top of transmission (Fig. 17).
Determine which traction relief valve is to be tested.
5. Disconnect hydraulic hose from transmission pump
outlet fitting for relief valve to be tested (Fig. 17):
Relief Valve to be Tested
Pump Outlet
Right Side Forward Port A
Right Side Reverse Port B
Left Side Forward Port C
Left Side Reverse Port D
6. Install hydraulic tester (pressure and flow) in series
with the pump outlet and the disconnected hose. Make
sure that the tester flow arrow points from the pump out-
let port and toward the hose for the relief valve direction
that is to be tested. Make sure the flow control valve
on the tester is fully open.
7. 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.
IMPORTANT: Do not run engine at full speed when
performing this test using Toro Hydraulic Tester
(Pressure and Flow) (TOR214678). Traction pump
output at full engine speed can damage hydraulic
tester.
8. Using a phototac to measure engine speed, move
throttle so engine speed is 2800 RPM (not full speed).
9. Completely close flow control valve on tester.
10.Leave traction control lever for transmission pump
not being tested in the neutral position.
11. While carefully monitoring tester pressure gauge,
have operator slowly push traction lever for pump being
tested (right side or left side) in direction being tested
(forward or reverse) until pressure gauge stabilizes indi-
cating that the relief valve has opened. Pressure gauge
should read approximately 4000 PSI (276 bar) as relief
valve lifts.
12.Release traction lever to the neutral position, open
tester flow control valve and stop engine. Record test re-
sults.
NOTE: The forward relief valves for the two (2) trans-
mission pump circuits are identical and thus can be in-
terchanged. The reverse relief valves are also identical.
The forward relief valves, however, are different than the
reverse relief valves so do not interchange forward and
reverse relief valves.
13.If traction relief valve pressure is not met, remove
and inspect relief valve from transmission (see Trans-
mission Service in the Service and Repairs section of
this chapter). Clean or replace relief valve. Relief valves
are not adjustable.
14.Relieve hydraulic system pressure (see Relieving
Hydraulic System Pressure in the General Information
section). Disconnect tester from pump outlet fitting and
hydraulic hose. Connect hose to pump fitting.
15.If necessary, repeat pressure test for other traction
relief valves.
Hydraulic
System