JLG sky trak mmv Service Manual page 371

Before troubleshoot-
ing any hydraulic cir-
cuit, ALWAYS begin
by checking the
following:
1. Hydraulic oil level in
the reservoir
2. All hoses, tubes,
fittings for leaks,
kinks, interference,
etc.
3. Air in the lines
NOTE:
When checking pressures
in circuits, refer to Section
9.7, Hydraulic System
Testing for correct
pressure readings.
Model MMV Rev. 12/04
If the fork side shift (right) is slow or
difficult, check the pressure at the
"VG" port of the unloader valve
If OK
Check the fork side shift valve.
If OK
Check packing in fork side shift cylinder
If OK
Check the right fork shift switch, fuse
and wiring
Hydraulic System
Adjust/repair/replace pressure reducing
Not
OK valve on the unloader valve
Not
Replace the fork side shift valve.
OK
Not
Repair/replace fork shift cylinder.
OK
Refer to the fork shift circuits and
Not
components in Section 10.7, Electrical
OK
System Troubleshooting
9.73