Isuzu KB P190. Manual - part 121

4B-40  REAR AXLE 

Inspection and Repair 

Make all necessary adjustments, repairs, and part
replacements if wear, damage, rust or other problems
are discovered during inspection. 

Visual Check 

Inspect the following parts for wear, damage or other
abnormal conditions. 

•  Friction disc 
•  Friction plate 
•  Spring plate 

1

 Sliding surface 

2 

 Protrusion 

  

 
 

 

425RS056

Pressure ring 

Check the parts for damage or other abnormal
conditions. 

3 

  Sliding surface for friction disc 

 

If dents or damages are discovered, grind them

with oil stone, and repair them with compound on

surface plate. 

4 

  Sliding surface of pressure ring inner surface and

pinion gear. 

5 

 Sliding surface of pressure ring bore and side

gear. 

6 

  sliding surface of pressure ring and side gear. 

7 

  Sliding surface of pressure ring and pinion shaft.

8 

  Mating surface to differential cage A. 

9 

  Burrs or dents on sliding surface of pressure ring

and rear differential cage should be repaired,

using oil stone. 

 

 

425RY00022

 

•  Thrust Washer 

10

  Groove on side gear circumference small burrs of 

dens should be repaired, using oil stone. 

11

 Sliding surface between side gear and thrust 

washer. 

425RY00024

 
•  Differential cage A and B 

12

  Contact surface to spring plate 

13

 Differential cage A and B contact surfaces to 

thrust washers Small burrs or dents should be 

repair, using oil stone. 

 

 

REAR AXLE  4B-41 

425RY00025

 

425RY00023

 

Friction Disc and Friction Plate 

•  Check friction disc and friction plate for distortion.
 

Limit : 0.08 mm 

 

 

 
 
 
 

 

 

425RS061

  

•  Check friction plate and friction disc for wear. 
 

Limit : (A-B)  

0.1 mm 

 

A : Protrusion Portion 

 

B : Sliding Portion 

 
 
 
 

 

 

425RS062

 

•  Check thrust washer for wear. 
 

Limit : 1.3 mm 

4B-42  REAR AXLE 

 

 

 

425RS063

 

Reassembly 

Adjustment of Clearance between 

Friction Disc and Plate 

1.  Measuring depth of differential case 

mm(in)

 

Standard (A-B) 

80.58 (3.17) 

(C) 10.58 

(0.42) 

 

 

425RS064

 

2.  Measuring overall length of pressure ring, friction

disc and plate assembly 
•  Assemble pinion shaft with pressure ring, then

friction disc and plate. 

•  Measure length between plates at both ends

over V-shape groove. (D) 

 

 

 
 

 

 

425RS065

 

3.  After A, B, C and D dimensions are measured, 

perform adjustment with the following procedure.
•  Measure spring plate : 
 

 

1.75 mm (0.069 in) 

× 4 pcs (E) 

•  Measure thickness of plate spring 
 

Standard dimension : 

 

 

1.75 mm (0.069 in) 

× 2 pcs (F) 

4.  Select a friction disc or plate so that ((A-B+C) -

(D+E) = 0.06 to 0.20 mm (0.002 to 0.008 in.) and 

also the difference in total dimension of friction 

disc and plate and spring plate (left/right side) 

does not exceed 0.05 mm (0.002 in.). 

  Thickness : 1.65, 1.75, 1.85 mm (0.065, 0.069, 

0.073 in) 

Adjusting Backlash of Side Gear in 
Axial Direction 

1.  Measuring depth of differential case 

mm(in)

 

Standard (F-B) 

82.03 (3.23) 

(G) 12.03 

(0.47) 

REAR AXLE  4B-43 

 

 

425RS066

 

2.  Measuring dimension between thrust washers at

both ends. 

 

Assemble side gear, pinion, pinion shaft pressure

ring and thrust washer. 
•  Eliminate clearance by pushing pressure ring

against the pinion shaft in axial direction. 

•  Eliminate backlash by connecting side gear to

the pinion. 

•  Measure dimension between thrust washers

at both ends. (H) 

 
 

 

 

425RS067

 

3. After each dimension is measured, perform

adjustment with the following procedure. 

 

Adjust so that ((F-B) + G-H) = 0.05 to 0.2 mm

(0.002 to 0.008 in). Also, select a proper thrust

washer so that the dimension difference from

back face of the pressure ring to thrust washer 

 

 

(left/right side) does not exceed 0.05 mm (0.002 

in). 

 

Thickness : 1.5, 1.6, 1.7 mm (0.059, 0.063, 0.067 

in) 

 

Note :  
When reassembling, sufficiently apply gear oil on 
every part, especially on sliding surface. 

1.  Install thrust washer in differential cage A and 

B. 

2.  Assemble spring plate, friction plate and 

friction disc as following illustration. 
•  Install spring plate with dished side turned 

to the differential cage side. 

425R300009

Legend 

  

1. 

Friction 

Plate 

  

2. 

Spring 

Plate 

  

3. 

Friction 

Disc 

 

 

4.  Install pressure ring and side gear. 

•  Fit two side gears in two pressure rings, one 

from under a ring and the other from above a 

ring. 

•  Fit two pairs of a friction disc and a friction 

plate under it on and under these two 

pressure rings. 

5.  Set pinion and pinion shaft on differential cage A 

assembly. 

6.  Assemble differential cage A and B. 

7.  Align the setting marks on differential cage A and 

B and tighten screws in diagonal order evenly.