1997 ISUZU TFS SERIES Workshop Manual

REAR AXLE 4B-53
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 pageOK OK
NG NG NG NG NG
OK
OK
Rear axle gear oil
Replace the differential side
bearingsW orn differential side bearings NG

4B-54 REAR AXLE
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 gearNG NG
Drive pinion and ring gear
backlash

REAR AXLE 4B-55
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 cageTighten the differential cage
bolts
Replace the shaft
Loose differential cage bolts
Too much spline play
OK
NG NG NG NO
OK OKAxle shaft

4B-56 REAR AXLE
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 pinionReplace the differential pinion
Replace the rear axle shaft
W orn differential pinion
W orn rear axle shaft splines
OK
NG NG NG NO
OK OKRear axle shaft

REAR AXLE 4B-57
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

4B-58 REAR AXLE
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 shaftNG NG
Rear hub bearing

REAR AXLE 4B-59
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

4B-60 REAR AXLE
2) Axle Case Leakage
Checkpoint Trouble Cause Countermeasure
Tighten the drain plug and/or
replace the gasket(s)Loose drain plug and/or
defective gasket(s) NG
Reapply the liquid gasket
Tighten the bolts to the
specified torque
Clean the air breather
Liquid gasket seal bad
Loose bolts
Air breatherClogged air breather
Differential carrier
Replace the axle caseAxle caseCracked axle case
NG NG NG NG
OK OK
OK
Oil filler and drain plug