Toro Groundsmaster 3280-D Service Manual page 142

Charge Pump Flow Test (Using Tester With Pressure Gauges
and Flow Meter) (Machine Serial Numbers below 316000000)
(continued)
Hydraulic System: Testing the Hydraulic System
6. Ensure that the flow control valve on the tester is fully open. Also, ensure
that the traction pedal and lift valve are in neutral and that the parking brake
is engaged.
7. Start engine and run at idle speed. Check for any hydraulic leakage from test
connections and correct before proceeding with test.
8. Run engine at full speed (3,150 to 3,250 rpm). Use a tachometer to verify
that the engine speed is correct.
The charge pump is a positive displacement pump. If the flow control
valve on the tester is fully closed, transmission damage can occur.
9. Watch tester pressure gauges carefully while slowly closing the flow control
valve until pressure gauge reads 3,450 kPa (500 psi).
10. Flow gauge reading should be at least 3.8 L/minute (1 gallon/minute).
11. Open flow control valve on tester and shut off engine. Record results of
hydraulic flow test.
12. If pressure of 3,450 kPa (500 psi) or flow of 3.8 L/minute (1 gallon/minute)
could not be achieved, check the following:
A. Perform the charge pressure test; refer to
Pressure Gauge) (Machine Serial Numbers below 316000000) (page
5–49). Also, a dynamic charge pressure test can be performed to identify
if a worn or damaged hydrostatic transmission exists.
B. Perform the implement relief pressure test; refer to
Pressure Test (Using Pressure Gauge) (Machine Serial Numbers below
316000000) (page
C. Inspect the condition of the charge pump gerotor and internal housing;
refer to Charge Pump Service in the Sauer-Danfoss (Sundstrand) 15
Series Service Manual at the end of this chapter.
D. The general condition of the transmission's piston pump and piston motor
might be suspected of wear and inefficiency.
13. Disconnect tester from the transmission and hydraulic hose. Connect
hydraulic hose to the transmission fitting. Check hydraulic-fluid level in
reservoir (front axle).
IMPORTANT
5–51).
Page 5–58
Charge Pressure Test (Using
Implement Relief
Groundsmaster ® 3280-D/3320
05138SL Rev B