JLG G12-55A Service Manual - Manual (Page 95)

6-7 G10-55A, G12-55A
Transmission
6.6 TROUBLESHOOTING
This section provides an easy reference guide covering
the most common problems that may occur during
operation of the transmission.
Note: Contact the local distributor if internal
transmission repair is required during the warranty
period.
The transmission should be checked, serviced and
repaired only by experienced service technicians who
are aware of all safety instructions and particular
component features
Problem Cause Remedy
1. Transmission will not engage
or will not shift properly.
1. Oil level too high or low. 1. Fill transmission to correct level
with hydraulic oil. Refer to
Section 2.4, “Fluid and
Lubricant Capacities.”
2. Transmission control lever not
functioning properly and/or a
fault in the wiring
harness.Transmission control
lever not functioning properly
and/or a fault in the wiring
harness.
2. Refer to Section 9.5, “Electrical
System Schematics.”
3. Transmission valve body
solenoids not functioning
properly.
3. Refer to Section 9.5, “Electrical
System Schematics.”
4. Pilot-operated shift valves not
operating properly.
4. Clean the valve spool and
housing. Replace return spring
as needed.
5. Pump output pressure low. 5. Refer to Section Note:, “Contact
the local distributor if internal
transmission repair is required
during the warranty period.,”
Problem 2. “Low or no pump
flow or pressure.”
6. Clutch piston o-rings damaged. 6. Replace o-rings.
7. Clutch discs worn or damaged. 7. Replace clutch discs.
8. Coupling shafts or gear teeth
damaged.
8. Replace couplings.