New Holland CX720 Repair Manual page 2796

11. Using the help of an assistant, switch the gearshift
selector to the neutral position. Record the pressure
readings on the test pressure gauges with the hydro-
static lever in neutral.
12. Move the hydrostatic lever into the forward position
and record the pressure gauge readings. Record the
pressure gauge readings with the hydrostatic lever in
the reverse position.
Make sure the area around the combine is clear be-
fore performing the following steps. Remain as far
away from the combine as possible when reading and
recording test pressures. Z102
13. Have the assistant switch the gear selector to posi-
tion "3" and engage the RWD switch. Record the
readings on the pressure test gauges with the hydro-
static lever in neutral.
14. While applying full pressure to the combine brakes,
have the assistant engage the hydrostatic lever in
forward and then reverse. Record the readings from
the test pressure gauges for each position of the hy-
drostatic lever.
15. Use the chart below to determine if the pressure
readings are within specified ranges. If the readings
are not within specifications, further troubleshooting
and/or testing will be necessary to determine the
cause of the problem. Sluggish or poor performance
may occur when the hydrostatic system charge pres-
sure drops below 24 bar (350 psi). When charge
pressure drops below 24 bar (350 psi), system pres-
sure is not high enough to allow the machine to move
or keep moving. The probable cause of low charge
pressure is most likely the result of excessive leak-
age in the hydrostatic system or the RWD system.
The motor case/E-T II valve leak test can be used to
determine if the fault lies within the drive motors or
E-T II valve.
NOTE: If low charge pressures or system pressures are
obtained, most likely a problem exists with the main hy-
drostatic system, not the RWD system. Performing hy-
draulic tests on the main hydraulic system before check-
ing the internals of the E-T II valve is advisable. Refer to
TRANSMISSION Hydrostatic - Troubleshooting (C.20.F
- G.40.A.10) for testing procedures.
16. If the RWD system is not engaging and the E-T II
valve spool solenoid is functioning properly, the main
valve spool in the valve may not be shifting. If charge
(pilot) pressure readings are correct, but forward and
reverse line pressure readings are NOT correct, the
main spool in the E-T II valve is not shifting and is
stuck in the "OFF" position.
TEST PRESSURES VS. MACHINE OPERATION
MODE
Control valve - Static description (D.14.E.14 -
C.30.A.20)
TRAVELLING - 2WD-4WD SYSTEM Hydrostatic
DANGER
2 4/7/2006
D.14.E / 42