Operation & Maintenance Manual──LG958L/LG959 Wheel Loader
96
3.8.2 Transmission System
No. Problems Possible Causes Remedy
1
Shifting
pressure of
every gear is
low
1 Low oil level in gearbox oil sump
2 Oil leakage in the main oil lines
3 Clogged oil filter of gearbox
4 Faulty converter charging pump
5 Improper adjustment of the
pressure-regulator valve in transmission
control valve
6 Invalid spring of pressure-regulator
valve in transmission control valve
7 Pressure-regulator valve of
transmission control valve or
accumulator piston is locked
1 Add oil to the specified level
2 Check the main oil lines
3 Clean or replace the filter
4 Disassemble and check the converter
charging pump or replace it
5 Readjust to the specified value
6 Change the spring of pressure
regulator valve
7 Disassemble and check to remove the
lock
2
Shifting
pressure of a
certain gear is
low
1 Damaged piston seal ring of this gear
2 Damaged gasket in the oil lines of this
gear
3 Oil leakage in the oil lines of this gear
1 Change the seal ring
2 Change the gasket
3 Check and remove the leakage
3
The oil of
torque converter
overheats
1 Low oil level in gearbox oil tank
2 High oil level in gearbox oil tank
3 Low shifting pressure and clutch slips
4 T/Q radiator is clogged
5 T/Q operates with high load for a
continuous long time
6 Radiator is not good
1 Add oil to the specified level
2 Drain oil to the specified level
3 Refer the problems 1 and 2
4 Clean or replace the radiator
5 Shut down for cooling
4
Machine can not
move when
engine runs in
high speed
1 Cut-off valve spool of transmission
control valve can’t reset
2 Shift no gear
3 Spring of pressure-regulator valve in
transmission valve is broken
4 Same as 1, 2, 3 and 4 of problem 1
1 Disassemble the cut-off valve, find
out the reasons that spool can’t reset
and remedy
2 Shift gear again or readjust the
gearshift control levers and linkages
3 Change the spring of
pressure-regulator valve
4 Refer to 1, 2, 3 and 4 of problem 1
5
Insufficient
driving force
1 Low shifting pressure
2 High oil temperature of T/Q
3 Damaged T/Q blades
4 Damaged overrunning clutch
5 Insufficient driving force of engine
1 Refer to problems 1 and 2
2 Refer to problems 3
3 Disassemble and check the torque
converter; change blades
4 Disassemble and check free-wheel
clutch, change damage parts
5 Check and maintain the engine