GROVE Published 10-21-2010, Control# 198-04 7-19
5540F/YB5515 SERVICE MANUAL TRANSMISSION AND TORQUE CONVERTER
Hydraulic 2/4-Wheel Drive Unit (Pressure
ON/Spring OFF)
4wd Cannot Be Engaged
In normal operation the 2/4-wheel drive clutch is spring
loaded off and therefore disengaged to give 2-wheel drive.
The clutch must be pressurised to give 4-wheel drive. Before
starting the more detailed fault finding procedures eliminate
the obvious:
1. Check that the transmission oil level is correct.
2. Check that the fuse for the 2/4WD circuit is intact.
3. Check that the 4-wheel drive external pipework is not
damaged and that the drive train is intact.
4. Check that all the electrical connections are clean and
secure. Also check that the solenoid spool is not sticking
(in the 2WD position).
5. Check that the mainline pressure is correct, see Low
Mainline Pressure.
6. Check that the pump flow rate is correct.
If the fault is not rectified after eliminating the obvious, check
the following:
2wd Cannot Be Engaged
No pressure is required to engage 2WD (spring loaded).
Check that the solenoid spool is not sticking (in the 4WD
position), then see below.
Possible Cause Remedy
7. Low mainline pressure 7. Identify if the fault is related to the 2/4WD disconnect:
a. Disconnect the external pipework to the 2/4WD
clutch. Cap and plug open orifices.
b. Check the mainline pressure - if the pressure is
correct, the fault must be within the 2/4WD (see step
8). If the reading is still low check the transmission in
the normal manner.
8. Low mainline pressure (due to 2/4WD clutch):
a. 2/4WD solenoid spool sticking.
b. 2/4WD solenoid spool O-ring failed.
c. Clutch shaft sealing rings leaking.
d. Excessive clutch shaft end float.
e. Clutch piston O-ring failed.
8. Rectify fault:
a. Strip, clean and re-assemble solenoid valve, renew
valve if required.
b. Renew O-ring.
c. Renew clutch shaft sealing rings.
d. Rectify fault, renew parts as required, reset end float
(should not exceed 0.001 in (0.03 mm))
e. Replace clutch piston O-ring.
9. Defective 2/4WD clutch:
a. Worn friction/counter plates
b. Mechanical failure of 4WD unit
c. Incorrect clutch pack end float.
9. Rectify fault:
a. Inspect friction/counter plates, renew as required.
b. Strip and inspect 4WD unit. Check that the electrical
and hydraulic circuits are functioning correctly.
c. Measure clutch pack end float (should be 0.002 to
0.004 in (0.04 to 0.09 mm)). Correct as required.
Possible Cause Remedy
10. Incorrect type of solenoid valve fitted 10. Check solenoid
Reference Only
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