Page 489 of 6020
REAR AXLE 4B-45
TROUBLESHOOTING
Refer to this Section to quickly diagnose and repai
r
rear axle problems.
Each troubleshooting chart has three headings
arranged from left to right.
(1) Checkpoint
(2) Trouble Cause
(3) Countermeasure
This Section is divided into five sub-sections:
1. Abnormal Rear Axle Noise 1) Noise when the engine is driving the vehicle
2) Noise when the vehicle is coasting
3) Intermittent noise
4) Noise when the vehicle is turning
5) Constant noise
2. Vibration
3. Oil Leakage 1) Differential carrier leakage
2) Axle case leakage
3) Axle case to inside hub leakage
4) Axle case to inside brake drum leakage
4. Power Not Being Transmitted to the W heels (Propeller Shaft Operation is Normal)
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ISUZU KB P190 2007
Page 490 of 6020
4B-46 REAR AXLE
1. ABNORMAL REAR AXLE NOISE
1) Noise when the Engine is Driving the Vehicle
Checkpoint Trouble Cause Countermeasure
Replenish the gear oilInsufficient gear oil
NG
Differential side bearingAdjust the differential side
bearing preload
Replace the drive pinion
bearings
Adjust the drive pinion bearing
preload
Replace the gear oil
Loose differential side
bearings
W orn drive pinion bearings
Loose drive pinion bearings
W rong or poor grade gear oil
Drive pinion to ring gear
backlash
Drive pinion end play
Adjust the backlashToo much or too little backlash
Continued on the next page OK
OK
NG
NG
NG
NG
NG
OK
OK
Rear axle gear oil
Replace the differential side
bearingsW orn differential side bearings
NG
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ISUZU KB P190 2007
Page 491 of 6020
REAR AXLE 4B-47
Checkpoint Trouble Cause Countermeasure
Replace the drive pinion and
the ring gear as a setExcessive ring gear run-out
Replace the drive pinion and
the ring gear as a setDrive pinion and/or ring gear
damage
NG
NGDrive pinion and ring gear
Continued from the previous page
Replace the drive pinion and
the ring gear as a setW orn drive pinion and ring
gear
NG
2) Noise when the Vehicle is Coasting
Checkpoint Trouble Cause Countermeasure
Replace the ring gear and the
pinion as a setRing gear damaged
Adjust the backlashInsufficient backlash
OK
Ring gear NG
NG
Drive pinion and ring gear
backlash
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ISUZU KB P190 2007
Page 492 of 6020
4B-48 REAR AXLE
3) Intermittent Noise
Checkpoint Trouble Cause Countermeasure
Axle case inside
Ring gear
Remove the foreign material
Replace the drive pinion and
the ring gear as a set
Foreign material in the axle
case
W arped ring gear
Differential cage
Tighten the differential cage
bolts
Replace the shaft
Loose differential cage bolts
Too much spline play
OK NG
NG
NG
NG
OK
OK
Axle shaft
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ISUZU KB P190 2007
Page 493 of 6020
REAR AXLE 4B-49
4) Noise when the Vehicle is Turning
Checkpoint Trouble Cause Countermeasure
Differential cross pin
Side gear
Replace the differential cross
pin
Replace the side gear
W orn differential cross pin
W orn side gear
Differential pinion
Replace the differential pinion
Replace the rear axle shaft
W orn differential pinion
W orn rear axle shaft splines
OK NG
NG
NG
NG
OK
OK
Rear axle shaft
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ISUZU KB P190 2007
Page 494 of 6020
4B-50 REAR AXLE
5) Constant Noise
Checkpoint Trouble Cause Countermeasure
Replace the rear axle shaftBent rear axle shaft
NG
Replace the side bearing
Replace the drive pinion
bearing
Replace the drive pinion and
the ring gear as a set
Replace the drive pinion and
the ring gear as a set
Flat spot on the side bearing
oil seal
BearingFlat spot on the drive pinion
Flat spot on the gear teeth
pilot bearing wear
Drive pinionFlat spot on the drive pinion
gear teeth
Ring gear
Replace the drive pinion and
the ring gear as a setW orn pinion splines oil seal
NG
NG
NG
NG
NG
OK
OK
OK
Rear axle shaft
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ISUZU KB P190 2007
Page 495 of 6020
REAR AXLE 4B-51
2. VIBRATION
Checkpoint Trouble Cause Countermeasure
Replace the rear axle shaftBent rear axle shaft
Replace the rear hub bearingW orn rear hub bearing
OK
Rear axle shaft NG
NG
Rear hub bearing
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ISUZU KB P190 2007
Page 496 of 6020
4B-52 REAR AXLE
3. OIL LEAKAGE
1) Differential Carrier Leakage
Checkpoint Trouble Cause Countermeasure
Correct the oil levelToo much gear oil
NG
Reapply the liquid gasket
and/or tighten the lock nut to
the specified torque
Reapply the liquid gasket
Tighten the bolts to the
specified torque
Replace the oil seal
Ring gear thrust boltLoose lock nut and/or liquid
Liquid gasket seal bed
Loose bolts
Oil sealW orn or defective oil seal
Differential carrier
Clean the air breatherAir breatherClogged air breather
NG
NG
NG
NG
NG
OK
OK
OK
OK
Gear oil level
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ISUZU KB P190 2007