1997 ISUZU TFS SERIES differential

4B-52 REAR AXLE
TROUBLESHOOTING
Refer to this Section to quickly diagnose and repair 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 Wheels (Propeller Shaft Operation is Normal)

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

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-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

4B-62 REAR AXLE
4. POWER NOT BEING TRANSMITTED TO THE WHEELS
(PROPELLER SHAFT OPERATION IS NORMAL)
Checkpoint Trouble Cause Countermeasure
Replace the rear axle shaftBroken rear axle shaft NG
Replace the drive pinion and
the ring gear as a setDrive pinion and ring gearBroken drive pinion and/or ring
gear
Replace the differential gears
and/or the spiderDifferential cage gearsBroken differential cage gears
and/or spider NG NG
OK OK
Rear axle shaft

4B-64 REAR AXLE
ITEM NO. ILLUSTRATION PART NO. PART NAME
RAL-34
9-8522-1272-0
(J-24254)Axle case oil seal installer
(for 194mm)
RAL-41
5-8840-0275-0
(J-37264) Differential holding fixture
RAL-40
5-8840-0003-0
(J-3289-20) Holding fixture base
RAL-44
5-8840-0013-0
(J-22888) Side bearing puller
RAL-9
9-8521-1743-0
(J-8107-2)Side bearing plug adapter
(for 194mm)
RAL-10
5-8840-2196-0
(J-8107-4)Side bearing plug adapter
(for 220mm)
RAL-50
5-8840-0133-0
(J-8614-01)Pinion flange holder
(for 194mm)
RAL-51
5-8840-2157-0
(J-37211)Pinion flange holder
(for 220mm)
RAL-539-8521-5032-0 Final pinion spindle