New Holland CX720 Repair Manual page 2828

2WD-4WD SYSTEM Hydrostatic - Troubleshooting (D.14.E -
G.40.A.10)
Problem
Performance of RWD is
sluggish or poor
RWD system is not
functioning
TRAVELLING - 2WD-4WD SYSTEM Hydrostatic
Possible Cause
Transmission is into high of a gear.
Air in system.
Main high pressure lines connected incor-
rectly.
Hydraulic lines/hoses pinched or kinked,
restricting oil flow.
Weak hydrostatic system high pressure re-
lief valve.
Excessive case leakage from RWD system
wheel motors or the E-T II valve.
Inadequate charge pressure.
Main hydrostatic system malfunction.
Blown fuse.
Low hydrostatic fluid level.
Hydrostatic filter clogged or broken.
RWD ON/OFF switch defective.
Open or broken electrical connection/wire
in RWD circuit.
Malfunctioning E-T II valve solenoid.
Main spool in E-T II valve or spool in drain
valve not shifting.
Excessive wheel motor leakage.
Switch transmission to a lower gear.
Determine source of air intake and repair
as necessary, bleed air from system.
Check routing of the high pressure lines.
Correct as necessary.
Check all the lines and the hoses. Repair
or replace as necessary.
Check the hydrostatic system relief valve.
Replace or adjust as necessary.
Inspect the components for leakage.
Check forward and reverse system pres-
sure and charge (pilot) pressure to engage.
Repair the wheel motor or replace the valve
as necessary.
Check forward and reverse system pres-
sure and charge (pilot) pressure to engage.
Repair the valve or the hydrostatic system
as necessary.
Check main hydrostatic system.
Check fuse. Replace as necessary.
Check hydrostatic fluid level. Add fluid as
necessary.
Inspect hydrostatic filters, replace as nec-
essary.
Test switch for proper operation.
Check circuit for open or broken wire/con-
nection.
Test solenoid for proper operation.
place as necessary.
Test E-T II valve spools for proper move-
ment. Replace valve as necessary.
Inspect wheel motors for leakage. Repair
or replace as necessary.
2 4/7/2006
D.14.E / 74
Correction
Re-