Isuzu KB P190. Manual - part 1048

UNIT REPAIR (AW30–40LE)

7A4–57

Direct Clutch Assembly (C-2)

Disassembled View

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Legend

(1) Direct clutch drum
(2) O-ring
(3) Direct clutch piston
(4) Piston return spring

(5) Snap ring
(6) Snap ring
(7) Flange
(8) Plate and disc

Five plates and five discs

7A4–58

UNIT REPAIR (AW30–40LE)

Disassembly

Remove direct clutch drum assembly from forward
clutch assembly.

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1. Check piston stroke of direct clutch (C–2).

Place the direct clutch assembly onto the OD
support assembly.

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Using a dial indicator, measure the direct clutch
piston stroke by applying and releasing compressed
air (390 – 780 kPa or 57 – 114 psi) as shown.

Pack clearance: 0.5 – 0.8 mm (0.020 – 0.031 in) 

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2. Remove the clutch drum thrust washer (Plastic)

from the rear end of direct clutch.

3. Remove the snap ring from the direct clutch drum.

4. Remove the flange, plates and discs.

5. Place special tool on the spring retainer and

compress the return spring. 
Using snap ring pliers, remove the snap ring.
Spring compressor : 5-8840-0254-0

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6. Remove the piston return spring.

UNIT REPAIR (AW30–40LE)

7A4–59

7. Place the direct clutch drum onto the OD support.

Holding the direct clutch piston by hand, apply
compressed air to the OD support to remove the
direct clutch piston.
Remove the direct clutch piston from direct clutch
drum.

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8. Remove two O-rings from piston.

Inspection and Repair

1. Check piston return spring.

Using calipers, measure the free length of the return
spring.

Standard length: 21.3mm (0.839 in)

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2. Check discs.

Using micrometer, measure the thickness of the
discs.

Minimum thickness: 2.04mm (0.0803in)

If the thickness is less than the minimum, replace
the disc.

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3. Check direct clutch piston.

Check that check ball is free by shaking the piston.
Check that the valve does not leak by applying
low-pressure compressed air.

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7A4–60

UNIT REPAIR (AW30–40LE)

4. Check direct clutch drum bushing.

Using a dial indicator, measure the inside diameter
of the clutch drum bushing.

Maximum inside diameter: 53.99mm (2.1256 in)

If the inside diamater is greater than the maximum,
replace the clutch drum.

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Reassembly

1. Coat new O-rings with ATF and install them on the

direct clutch piston.

2. Install direct clutch piston to direct clutch drum.

Being careful not to damage the O-rings, press in
the direct clutch piston into the clutch drum, using
both hands.

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3. Install piston return spring.

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4. Compress piston return spring and install snap ring

in groove.

• Place special tool on the spring retainer, and

compress the return spring.

• Install the snap ring with snap ring pliers. 

• Be sure the end gap of the snap ring is not

aligned with the spring retainer claw.

Spring compressor: 5-8840-0254-0

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