Isuzu N-Series. Manual - part 851

MANUAL TRANSMISSION 7B-65

Disassembly

1. Remove simultaneously the following parts with a

press using a bearing remover; the bearing, spac-
er, collar, reverse gear, needle bearing, reverse
block ring, 1st-reverse clutch hub assembly &
sleeve, 1st block ring, 1st outside ring, 1st inside
ring, 1st gear, and needle bearing.

2. Disassemble the 1st-reverse clutch hub & sleeve.

3. Remove the 4th-5the clutch hub assembly fixing

snap ring using snap ring pliers.

4. Remove simultaneously the following parts with a

press using a bearing remover; the 4th-5th clutch
hub assembly & sleeve, 5th block ring, 5th gear,
needle bearing.

Legend

1. Snap ring

17. 3rd outside ring

2. 4th-5th clutch hub assembly and sleeve

18. 3rd inside ring

3. 5th block ring

19. Main shaft

4. 5th gear

20. Needle bearing

5. Needle bearing

21. 1st gear

6. Snap ring

22. 1st inside ring

7. Collar

23. 1st outside ring

8. Needle bearing

24. 1st block ring

9. 3rd gear

25. Bearing

10. Needle bearing

26. Spacer

11. 2nd gear

27. Collar

12. 2nd inside ring

28. Needle bearing

13. 2nd outside ring

29. Reverse gear

14. 2nd block ring

20. Reverse block ring

15. 2nd-3rd clutch hub assembly and sleeve

31. 1st-reverse clutch hub assembly & sleeve

16. 3rd block ring

N7A1195E

Legend

1. Clutch hub
2. Sleeve
3. Ball
4. Block
5. Spring

N7A0372E

7B-66 MANUAL TRANSMISSION

5. Disassemble the 4th-5th clutch hub assembly &

sleeve.

6. Remove the 3rd gear collar fixing snap ring using

snap ring pliers.

7. Remove simultaneously from the main shaft the

following parts with a press using a bearing remov-
er; the collar, 3rd gear, needle bearing, 3rd inside
ring, 3rd outside ring, 3rd block ring, 2nd-3rd clutch
hub assembly & sleeve, 2nd block ring, 2nd out-
side ring, 2nd inside ring, 2nd gear, and needle
bearing.

8. Disassemble the 2nd-3rd clutch hub assembly &

sleeve.

Inspect each part, and if any wear, damage and
other abnormality is found, repair or replace the
item.

9. Inspect each bearing with respect to the following

items, and if any abnormality is found, replace the
part.

• Smoothness of rotation
• Noise
• Abnormal external appearance, including dam-

age, rust, etc.

Legend

1. Spring
2. Insert
3. Clutch hub
4. Sleeve

N7A1197E

N7A1143E

Legend

1. Clutch hub
2. Sleeve
3. Ball
4. Block
5. Spring

N7A1199E

N7A1200E

MANUAL TRANSMISSION 7B-67

• Abnormal free play in thrust direction

10. Inspect the internal diameter of the gear.

• Measure the inside diameter of each gear us-

ing an inside dial gauge.

• If the measured value exceeds the limit, re-

place the gear.

11. Main shaft deflection

• Measure the deflection of the main shaft using

a dial gauge.

• If the measured value exceeds the limit, re-

place the main shaft.
Standard: 0.015 mm (0.000059 in)
Limit: 0.1 mm (0.00393 in)

12. Inspect the synchromesh system.

• Inspect the components, and repair light

stepped wear and damage using an oil stone or
a pencil grinder.

13. Clearance between block ring and dog gear

• Measure the clearance using a thickness

gauge.

• If the measured value exceeds the limit, re-

place the block gear.

Gear Internal Diameter, mm (in)

Standard

Limit

5th gear

44.009 — 44.025

(1.732 — 1.733)

44.065

(1.734)

3rd gear

63.010 — 63.029

(2.480 — 2.481)

63.069

(2.483)

2nd gear

63.010 — 63.029

(2.480 — 2.481)

63.069

(2.483)

1st gear

63.010 — 63.029

(2.480 — 2.481)

63.069

(2.483)

Reverse Gear

63.010 — 63.029

(2.480 — 2.481)

63.069

(2.483)

N7A1201E

Clearance between Block Ring and Dog Gear, mm
(in)

Standard

Limit

4th / 5th / Reverse

1.30 — 2.60

(0.051 — 0.102)

0.5 (0.019)

2nd / 3rd

1.00 — 2.50

(0.039 — 0.098)

0.5 (0.019)

1st

1.00 — 2.50

(0.039 — 0.098)

0.5 (0.019)

N7A1202E

N7A1203E

7B-68 MANUAL TRANSMISSION

14. Inspect the sliding part, spline part, inserting part

and insert groove of the clutch hub and sliding
sleeve for wear and damage.

15. Measure the free play in the direction of spline ro-

tation on the clutch hub external circumference.

• If the measured value exceed the limit, replace

the part.

16. Measure the clearance between the insert and

block ring groove using a caliper.

• If the measured value exceeds the limit, re-

place the insert and block ring.

17. Measure the clearance between the insert and

clutch hub using a thickness gauge.

• If the measured value exceeds the limit, re-

place the insert and clutch hub.

Legend

1. Block ring
2. Outside ring
3. Inside ring

Spline Free Play, mm (in)

Standard

Limit

0 — 0.05 (0 — 0.0019)

0.3 (0.0118)

N7A1204E

N7A1205E

Clearance between Insert and Block Ring Groove,
mm (in)

Standard

4th / 5th

3.46 — 3.76 (0.136 — 0.148)

Clearance between Insert and Clutch Hub, mm (in)

Standard

4th / 5th

0.01 — 0.21 (0.00039 — 0.00826)

N7A1206E

N7A1207E

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