Isuzu N-Series. Service manual - part 173

REAR AXLE 4B-49

Adjusting shims available,
0.10, 0.12, 0.14, 0.16, 0.18, 0.20 mm (0.004, 0.0047,
0.0055, 0.0063, 0.0071, 0.0079 in)

N4A0155E

TOOTH CONTACT

CASE

ADJUSTMENT PROCEDURE

Drive pinion is too far 
away from ring gear.

1. Move the drive pinion in to-

ward the ring gear by de-
creasing the thickness of 
pinion depth adjusting 
shims.

2. Adjust the backlash by 

moving ring gear away 
from the drive pinion.

Drive pinion is too close to 
the ring gear.

1. Move the drive pinion away 

from the ring gear by in-
creasing thickness of pin-
ion depth adjusting shims.

2. Adjust the backlash by 

moving ring gear in toward 
the drive pinion.

Ring gear is too close to 
the drive pinion.

1. Move the drive pinion in to-

ward the ring gear by de-
creasing thickness of 
pinion depth adjusting 
shims.

2. Adjust the backlash by 

moving ring gear away 
from the drive pinion.

Ring gear is too for away 
from drive pinion.

1. Move the drive pinion away 

from the ring gear by in-
creasing thickness of pin-
ion depth adjusting shims.

2. Adjust the backlash by 

moving ring gear in toward 
the drive pinion.

N4A0156E

N4A0160E

N4A0157E

N4A0161E

N4A0158E

N4A0162E

N4A0159E

N4A0163E

4B-50 REAR AXLE

9. Lock Plate

Tighten:
Lock plate bolt to

• 292 mm differential: 29 N

⋅m (3.0 kg⋅m / 22 lb⋅ft)

• 320 mm differential: 13 N

⋅m (1.3 kg⋅m / 9 lb⋅ft)

The lock plates are available in 2 different kinds to per-
mit gradual adjustment by 1/2 notch of the adjust nut.

Differential Cage Assembly

This illustration is based on the 292 mm differential

N4A0189E

Legend

1. Side bearing inner race

6. Differential pinion

2. Differential cage B

7. Side gear

3. Side gear

8. Thrust washer

4. Thrust washer

9. Differential cage A and ring gear

5. Spider

N4A0190E

REAR AXLE 4B-51

Disassembly

1. Side Bearing Inner Race

Remover:
9-8521-0061-0 (292 mm)
5-8840-2373-0 (320 mm)
Adapter:
9-8521-2701-0

2. Differential Cage B

Apply a setting mark before removing the differen-
tial cage B to ensure reassembly into original posi-
tion.

3. Side Gear
4. Thrust Washer
5. Spider
6. Differential Pinion
7. Side Gear
8. Thrust Washer
9. Differential Cage A and Ring Gear

Inspection and Repair

Make necessary correction or parts replacement if wear,
damage or any other abnormal conditions are found
through inspection.
Visual Check
Inspect the following parts for wear, damage or other ab-
normal conditions.

• Gear
• Bearing
• Oil  seal
• Differential cage
• Drive pinion

Ring Gear Replacement
The ring gear should always be replaced together with
the drive pinion as a matched set.
When installing ring gear, apply stud lock to the thread
holes and bolts after treatment of the bolts with primer N.

Ring gear bolt wrench; 
5-8840-2830-0 (for 292 mm differential)

Tighten:
Ring gear bolt to

• 292 mm differential: M12 bolt (E12) to 127 N

⋅m (13

kg

⋅m / 94 lb⋅ft), M14 bolt to 181 N⋅m (18.5 kg⋅m / 133

lb

⋅ft)

• 320 mm differential: 333 N

⋅m (34 kg⋅m / 246 lb⋅ft)

Clearance between Spider and Differential Pinion

• 292 mm differential

Standard: 0.07 — 0.13 mm (0.003 — 0.005 in)
Limit: 0.2 mm (0.008 in)

• 320 mm differential

Standard: 0.05 — 0.13 mm (0.002 — 0.005 in)
Limit: 0.2 mm (0.008 in)

N4A0191E

N4A0192E

N4A0194E

4B-52 REAR AXLE

Clearance between Side Gear and Differential Cage

• 292 mm differential

Standard: 0.05 — 0.11 mm (0.002 — 0.004 in)
Limit: 0.25 mm (0.01 in)

• 320 mm differential

Standard: 0.13 — 0.20 mm (0.005 — 0.008 in)
Limit: 0.25 mm (0.01 in)

Play in Spline between Side Gear and Axle Shaft

• 292 mm differential

Standard: 0.08 — 0.15 mm (0.003 — 0.006 in)
Limit: 0.3 mm (0.012 in)

• 320 mm differential

Standard: 0.2 mm (0.008 in)
Limit: 0.5 mm (0.02 in)

REASSEMBLY

1. Differential Cage A and Ring Gear
2. Thrust Washer
3. Side Gear
4. Differential Pinion
5. Spider
6. Thrust Washer
7. Side Gear
8. Differential Cage B

1) Install by aligning setting marks.
2) Apply oil to threaded portion of bolts before in-

stallation.

Tighten:
Differential cage B nut to

• 292 mm differential: 54 N

⋅m (5.5 kg⋅m / 39.8 lb⋅ft)

• 320 mm differential: 74 N

⋅m (7.5 kg⋅m / 54.6 lb⋅ft)

3) Measure the clearance between the back face

of the side gear and the differential cage B by
inserting a feeler gauge through the hole on the
cage B.

Clearance,
292 mm differential: 0.21 — 0.28 mm (0.008 — 0.011 in)
320 mm differential: 0.10 — 0.38 mm (0.004 — 0.015 in)
When the clearance exceed a limit, replace the thrust
washer or side gear.

Legend

1. Side gear
2. Differential gear

N4A0174E

N4A0175E

N4A0176E