Isuzu N-Series. Manual - part 172

REAR AXLE 4B-45

292 mm/320 mm Rear Differential

Major Components

This illustration is based on the 292 mm differential.

Legend

1. Lock plate

6. Drive pinion cage assembly

2. Bearing cap

7. Shim

3. Adjust nut

8. Pilot bearing retainer

4. Side bearing outer race

9. Pilot bearing

5. Differential cage assembly

N4A0178E

4B-46 REAR AXLE

Disassembly

1. Lock Plate
2. Bearing Cap

Set the differential assembly onto a special fixture.
Apply a setting mark to the right and left side bear-
ing caps to prevent interchanging.

3. Adjust Nut
4. Side Bearing Outer Race

Keep the side bearing outer race and inner races
separate to prevent interchanging.

5. Differential Cage Assembly

6. Drive Pinion Cage Assembly

7. Shim
8. Pilot Bearing Retainer
9. Pilot Bearing

Reassembly

1. Pilot Bearing
2. Pilot Bearing Retainer

The fixing nut should be on the inboard side of the
case.

3. Differential Cage Assembly
4. Side Bearing Outer Race

Install the outer and inner races, so that original
combination is maintained.

N4A0179E

N4A0137E

Legend

1. Setting mark
2. Pinion cage
3. Shim

N4A0180E

N4A0181E

REAR AXLE 4B-47

5. Bearing Cap

Install the bearing caps by aligning setting marks
(1) applied at disassembly.

6. Adjust Nut

1) Threaded groove in nut should be properly

aligned with threaded groove in the carrier.

2) Tighten the adjust nuts so that they can be

turned after installing and semi-tightening bear-
ing caps.

Inspection of Ring Gear for Run-Out

• 292 mm differential

Standard: 0.05 mm (0.002 in)
Limit: 0.2 mm (0.008 in)

• 320 mm differential

Standard: 0.08 mm (0.003 in)
Limit: 0.25 mm (0.010 in)

7. Shim
8. Drive Pinion Cage Assembly

Install the shim removed and pinion aligning the oil
hole or setting mark applied on removal.

Tighten:
Drive pinion cage bolt to

• 292 mm differential: M12 bolt to 69 N

⋅m (7.0 kg⋅m / 51

lb

⋅ft), M14 bolt to 78 N⋅m (8.0 kg⋅m / 58 lb⋅ft)

• 320 mm differential: 72 N

⋅m (7.3 kg⋅m / 53 lb⋅ft)

N4A0137E

N4A0182E

N4A0183E

N4A0184E

4B-48 REAR AXLE

Backlash between Drive Pinion and Ring Gear
Backlash,
292 mm differential: 0.18 — 0.23 mm (0.007 — 0.009 in)
320 mm differential: 0.19 — 0.29 mm (0.007 — 0.011 in)

Bearing preload,
N.S.K. bearing: 5.7 — 13.0 N (0.58 — 1.33 kg / 1.3 —
2.9 lb)
Koyo bearing 11.5 — 17.9 N (1.17 — 1.83 kg /2.6 — 4.0
lb)

Side Bearing Preload Adjustment
Thread the adjust nut on the ring gear side into 2 notch-
es to give a proper bearing preload when correct back-
lash and tooth contact are obtained.
Fully tighten the bearing cap bolts.

Tighten:
Bearing cap bolt to

• 292 mm differential: 108 N

⋅m (11 kg⋅m / 80 lb⋅ft)

• 320 mm differential: 157 N

⋅m (16 kg⋅m / 116 lb⋅ft)

Recheck the backlash after tightening the bearing cap
bolts.

Inspection of Drive Pinion and Ring Gear Tooth
Contact

• Apply a thin coat of red check to the faces of the 7

— 8 teeth of the ring gear.

• Check the impression of contact (Right contact)

obtained on the ring gear teeth and make neces-
sary adjustment as described below if the contact
is abnormal.

N4A0185E

N4A0186E

N4A0187E

N4A0188E