GROUP 2 OPERATIONAL CHECKS AND TROUBLESHOOTING

1. POWER TRAIN OPERATIONAL CHECKS

This procedure is designed so that the mechanic can make a quick check of the system using a
minimum amount of diagnostic equipment. If you need additional information, read Structure and
function, Group 1.
A location will be required which is level and has adequate space to complete the checks.
The engine and all other major components must be at operating temperature for some checks.
Locate system check in the left column and read completely, following the sequence from left to right.
Read each check completely before performing.
At the end of each check, if no problem is found(OK), that check is complete or an additional check is
needed. If problem is indicated(NOT OK), you will be given repair required and group location.
If verification is needed, you will be given next best source of information :

Chapter 2 : Troubleshooting
Group 3 : Tests and adjustments

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 Transmission oil must be at operating temperature for these checks.

Item Description Service action

Transmission oil warm- Start engine. Apply service OK

up procedure brakes and release parking brake. Check completed.
Select full automatic switch to
manual mode.
Move gear selector lever to 3rd
speed.
Move gear selector lever to
forward "F" position.
1
2 Increase engine speed to high idle
for 30 seconds.
A

Move gear selector lever to

neutral "N" position and run for 15
seconds.
1

4
2
3
F
N
R
Repeat procedure until
transmission temperature gauge
arrow points to bar above dial.

Gear selector lever and Move gear selector lever to each OK

neutral lock latch 1

4
2
3
position. Check completed.
checks
NOTE : Gear selector lever
Engine OFF. NOT OK
position changes slightly as
Repair lock or replace
steering column is tilted.
switch.
FEEL : Lever must move freely
through all positions.
Engage neutral lock.
Apply slight effort to move lever
into forward(F) and reverse(R).
LOOK : Neutral lock must stay
engaged.

Automatic shifting Start engine. OK

check Check completed.
Move gear selector lever to 4th
speed.
1

4
2
3
F
N
R
NOT OK
Go to transmission error
Turn full automatic switch ON.
code group at page 3-27~
LOOK : Automatic sign on
Automatic sign 3-53.
display.
Repair or replace the
Move gear selector lever to display or harness.
forward or reverse position.
Increase engine rpm.
LOOK : Speed(2nd~4th) on
display must vary with machine
speed.

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 Item Description Service action

Transmission noise Run engine at approximately OK

check 1

4
2
3
1600rpm. Check completed.
Engine running.
Drive unit with transmission in NOT OK
each forward and reverse speed. Go to transmission makes
excessive noise group 3.
LISTEN : Transmission must not
make excessive noise in any
range.
Engine rpm must not "lug down"
as unit is shifted between gears.

Transmission "quick Release parking brake and select OK

shift" check full automatic switch to manual Check completed.
Engine running. mode.
NOT OK
Shift to 2nd forward. Check connector at base
of control valve.
Drive machine at approximately
5km/h and press gear selector IF OK
lever kick down switch or RCV Go to transmission
lever switch once. controller circuit in group
1.
LOOK/FEEL : Transmission must
shift to and remain in 1st gear.
Press gear selector lever kick
down switch once.
1
2
3
4

LOOK/FEEL : Transmission must

shift back to 2nd gear.
Shift to (3rd or 4th) gear and press
gear selector lever kick down
switch once.
LOOK/FEEL : Transmission must
not shift down.
Select full automatic switch to
automatic mode.
Drive machine at approximately
90% speed of max speed in each
gear(2nd or 3rd or 4th).
Shift to(2nd or 3rd or 4th) gear in
each forward and reverse speed
and press gear selector kick down
lever switch or RCV lever switch
once.
LOOK/FEEL : Transmission must
shift to lower(1st or 2nd or 3rd)
gear respectively.
Press gear selector lever kick
down switch or RCV lever switch
once again.

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 Item Description Service action

LOOK/FEEL : Transmission
must shift to former(2nd or 3rd or
4th) gear.
NOTE : If gear selector lever kick
down switch or RCV lever switch
is pressed twice, transmission will
shift down the immediately back
to former gear.
Forward, reverse and Park unit on level surface. OK
4th speed clutch pack 1
2
3
Check completed.
Apply service brakes.
4

drag check
NOT OK
Transmission must Move gear selector lever to
If unit moves, repair
be warmed up for neutral.
transmission.
this check.
Move gear selector lever to 1st.
Engine running.
Release parking brake and
service brakes.
Run engine at low idle.
LOOK : Unit must not move in
either direction.
NOTE : If unit moves forward,
either the forward pack or the 4th
speed pack is dragging.

Transmission shift Run engine at approximately OK

modulation check 1
2
1300rpm. Check completed.
3

Engine running.
4

Put transmission in 1st forward, NOT OK

shift several times from forward to Go to unit shifts too fast,
reverse and reverse to forward. chapter 2 in this group.
Repeat check in 2nd gear.
LOOK : Unit must slow down and
change direction smoothly.

Torque converter check Start engine. Apply service OK

1

4
2
3
brakes and release parking brake. Check completed.
Move gear selector lever to 3rd NOT OK
speed. If stall rpm are too low or
too high, problem may be
Move gear selector control lever
engine power or torque
to forward "F" position.
converter.
Increase engine speed to high
IF OK
idle.
Replace transmission
LOOK : Torque converter stall torque converter.
rpm must be within the following
range.
Stall rpm : 202070rpm
Move gear selector control lever
to neutral "N" position and run for
15 seconds.

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2. TROUBLESHOOTING
1) TRANSMISSION
Diagnose malfunction charts are arranged from most probable and simplest to verify, to least
likely, more difficult to verify. Remember the following steps when troubleshooting a problem :
Step 1. Operational check out procedure(See group 3 in section 1.)
Step 2. Operational checks(In this group.)
Step 3. Troubleshooting
Step 4. Tests and/or adjustments(See group 3.)

Problem Cause Remedy

Transmission slippage Low oil level. Add oil.

Wrong oil grade. Change oil.
Restricted transmission pump Remove and clean screen.
suction screen.
Leak in transmission control valve Remove valve and inspect gaskets.
or gasket.
Low transmission pump flow due Do transmission pump flow test.
to worn pump.
Weak or broken pressure regulat- Do transmission system pressure test.
ing valve spring.

Error code on display Something wrong in transmission. Go to transmission error code group at page
3-27~3-53.

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 Problem Cause Remedy

Machine will not move Low oil level. Add oil.

Applied park brake. Check parking brake fuse.
Check continuity to parking brake switch.
No power to transmission contro- Check transmission controller fuse.
ller.
Malfunctioning parking brake Remove and inspect parking brake solenoid
solenoid valve. valve.
Check for power to solenoid valve.
Restricted orifice of PPC valve. Remove orifice and check for contamination
and/or plugging.
(Do not remove valve housing for this purpose.)
Excessive leakage in Do transmission element leakage test using
transmission element. system pressure.
Worn clutch disks. Repair transmission.
Low or no transmission See transmission pressure is low in this group.
pressure.
Service brake will not release. Do brake pedal operational check.
Do service and park system drag checks.
Failed torque converter. Do torque converter stall test.
If engine pulldown in normal, torque converter is
good.
Broken shafts or gears. Drain transmission to determine if large pieces
of metal contamination are present.
Broken drive shafts. Inspect drive shafts and universal joints for
external damage. Repair.

Broken ring or pinion gear. If drive shaft rotate with transmission in gear but
machine does not move, a differential failure is
indicated. Repair.

Machine does not Malfunctioning transmission Check solenoid valve.

engage in low gear control solenoid valve.
Stuck spool in transmission Remove and inspect transmission control valve
control valve. spools.
Stuck PPC valve. Remove end cover to inspect PPC valve.
Replace if necessary.
Malfunctioning transmission Check speed sensor.
speed sensor.

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 Problem Cause Remedy

Transmission pressure is Low oil level. Check transmission oil level and refill if
low(All gears) necessary.
Failed transmission pressure Verify transmission system pressure. Do
switch. transmission system pressure test.
Plugged suction strainer. Transmission pump may be noisy if transmission
suction screen is clogged. Drain transmission.
Remove and clean suction screen.
Also, check condition of transmission filter.
Stuck transmission pressure Remove transmission pressure regulating valve.
regulating valve or broken spring. Inspect for damage(See transmission control
valve).
Failed control valve gasket. Inspect transmission control valve for external
leakage. Remove control valve.
Inspect or replace gasket.
Stuck PPC valve. Remove end cover to inspect modulation spool
and check torque on cap screws retaining
control valve to transmission.

Transmission system Failed transmission pump. Do pump flow test.

pressure is low (One or
Failed transmission control valve Inspect transmission control valve for external
two gears)
gasket. leakage. Remove control valve.
Inspect or replace gasket.
Leakage in clutch piston or seal Disassemble and repair.
ring.

Transmission shifts too Low oil level(Aeration of oil). Add oil.

low
Low transmission pressure. Do transmission system pressure test.
Restricted transmission pump Remove and clean screen.
suction screen.
Low transmission pump flow. Do transmission pump flow test.
Excessive transmission Do transmission element leakage test using
element leakage. system pressure.
Stuck PPC valve. Remove end cover to inspect modulation spool.
Replace if necessary.
Restricted PPC valve orifice. Remove orifice and inspect for contamination
and /or plugging.
Restricted oil passages between Remove control valve and inspect oil passage.
control valve and transmission
elements.
Incorrect transmission oil. Change oil(SAE 10W-30/15W-40)

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 Problem Cause Remedy

Transmission shifts too Wrong transmission controller. Check if transmission controller has been
fast changed
System pressure too high. Do transmission system pressure test.
Stuck PPC valve. Remove and inspect PPC valve.
Replace if necessary. Also remove end cover to
inspect PPC valve and control valve housing.
Replace if necessary.
Stuck or missing check valves. Inspect transmission control valve.
Missing O-ring from end of Remove orifice and inspect port for O-ring.
modulation orifice.
Broken piston return spring. Disassemble and inspect clutch.
Incorrect transmission oil. Change oil(SAE 10W-30/15W-40)

Machine "creeps" Warped disks and plates in Check transmission.

in neutral transmission.

Transmission hydraulic High oil level. Transmission overfilled or hydraulic pump seal
system overheats leaking.
Low oil level. Add oil.
Wrong oil grade. Change oil.
Park brake dragging. Check for heat in park brake area.
Pinched, restricted or leaking lube Check cooler lines.
lines.
Machine operated in too high gear Operate machine in correct gear range.
range.
Malfunction in temperature gauge Install temperature sensor the verify temperature.
or sensor. Do tachometer/temperature reader installation
procedure.
Restricted air flow through oil Do radiator air flow test.
cooler or radiator.
Failed oil cooler bypass valve(In Disassemble and inspect.
thermal bypass valve).
Failed thermal bypass valve. Remove thermal bypass valve and check to see
if machine still overheats. Do transmission oil
cooler thermal bypass valve test.
Internally restricted oil cooler. Do oil cooler restriction test.
Leakage in transmission hydraulic Do transmission system pressure, element
system. leakage test.
Malfunction in converter relief Do converter out pressure test.
valve.
Low transmission pump output. Do transmission pump flow test.

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 Problem Cause Remedy

Excessive transmission Too low engine low idle. Check engine low idle speed.
noise(Under load or no
Worn parts or damaged in Remove transmission suction screen. Inspect
load)
transmission. for metal particles.
Repair as necessary.
Warped drive line between engine Inspect drive line.
and torque converter.
Low or no lube. Do converter-out and lube pressure test. Do
transmission pump flow test.

Foaming oil Incorrect type of oil. Change oil.

High oil level. Transmission overfilled or hydraulic pump seal
leaking.
Low oil level. Add oil.
Air leak on suction side of pump. Check oil pickup tube on side of transmission.

Oil ejected from dipstick Plugged breather. Inspect breather on top of transmission.
Replace.

Machine vibrates Aerated oil. Add oil.

Low engine speed. Check engine speed.
Failed universal joints on Check universal joints.
transmission drive shaft or
differential drive shafts.

Machine lacks power Engine high idle speed set too Check high idle adjustment.
and acceleration low.
Incorrect transmission oil. Change oil.
Aerated oil. Add oil.
Low transmission pressure. Do transmission system pressure test.
Warped transmission clutch. Do transmission clutch drag checks.
Torn transmission control valve Inspect gasket.
gasket.
Brake drag. Do brake drag check.
Failed torque converter. Do torque converter stall speed test.
Low engine power. Do engine power test.

Torque converter stall Aerated oil. Put clear hose on thermal bypass outlet port.
RPM too high Run machine to check for bubbles in oil.
Stuck open converter relief valve. Do converter-out pressure test.
Leakage in torque converter seal. Do converter-out pressure test.
Torque converter not Replace torque converter.
transferring power(Bent fins,
broken starter).

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 Problem Cause Remedy

Torque converter stall Low engine power. Do engine power test.

RPM too low
Mechanical malfunction. Remove and inspect torque converter.

Transmission pressure Low oil level. Add oil.

light comes ON when
Cold oil. Warm oil to specification.
shifting from forward to
reverse(All other gears Leak in reverse pack. Do transmission pressure, pump flow, and
OK) leakage check.

Transmission pressure Cold oil. Warm oil to specification.

light comes ON for each
No time delay in monitor. Do monitor check.
shift
Restriction in modulation orifice. Remove orifice and inspect for restriction and/or
plugging.
Stuck PPC valve. Remove and inspect.
Low transmission pressure circuit. Do transmission system pressure test.

Leak in transmission pressure Do converter out pressure test.

circuit.
Failed transmission pump. Do transmission pump flow test.
Clogged filter. Inspect filter. Replace.

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 2) DIFFERENTIAL / AXLE

Problem Cause Remedy

Differential low on oil External leakage. Inspect axle and differential for leaks.

Excessive differential Low oil level in differential. Check oil. Remove drain plug and inspect for
and/or axle noise metal particles in differential case.
Disassemble and determine cause.
Incorrect type of oil. Change oil
Dragging brakes. Do brake check.
Failed pinion bearing. Remove and inspect pinion.
Check to ensure pinion housing was indexed.
Incorrect gear mesh pattern Remove pinion gear housing and inspect ring
between ring and pinion gear. and pinion gear.
Failed differential pinion gears Remove differential housing drain plug and
and/or cross shafts. inspect for metal particles. Disassemble and
inspect.
Failed axle bearing. Do axle bearing adjustment check.
Mechanical failure in axle Remove differential. Inspect, repair.
planetary.

Oil seeping from outer Excessive end play in axle. Do axle bearing adjustment check.
axle seal
Worn outer bearing and/or cup. Disassemble and inspect outer axle bearing,
cup, spacer, and seal. Replace, if necessary.
Overfilled differential. Check differential oil return system for excessive
internal restriction.

Axle overheats Low differential oil. Add oil.

Overfilled differential. See differential overfills with oil in this group.
Brake drag. See brakes drag in this group.

3) DRIVE LINE

Problem Cause Remedy

Excessive drive line Yokes not in line on drive shafts. Inspect. Align drive shaft yokes.
vibration or noise
Worn front drive line support Inspect, repair.
bearing.
Bent drive shaft. Inspect all drive shafts. Replace.
Loose yoke retaining nuts(Drive Inspect. Replace.
shafts wobble at high speed).
Rear axle oscillating support. Inspect, repair.
Lack of lubrication. Lubricate with proper grade of grease.

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