piston ISUZU TF SERIES 2004 Workshop Manual

7A4–58 UNIT REPAIR (AW30–40LE)
Direct Clutch Assembly (C-2)
Disassembled View
2 48R20 0001
E nd O FCallo ut
Legend
(1) Clutch drum thrust washer (Plastic)
(2) Snap ring
(3) Flange
(4) Plate and disc
Five plates and five discs(5) Snap ring
(6) Piston return spring
(7) Direct clutch drum
(8) Direct clutch piston
(9) O-ring

UNIT REPAIR (AW30–40LE) 7A4–59
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: 0.4 – 0.7 mm (0.016 – 0.028 in)
RUW3 7A SH00 4901
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 : J–25048
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6. Remove the piston return spring.

7A4–60 UNIT REPAIR (AW30–40LE)
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: 21.3 mm (0.839 in)
24 7RY 0 003 4
2. Check discs.
Using micrometer, measure the thickness of the
discs.
Minimum thickness: 2.04 mm (0.0803 in)
If the thickness is less than the minimum, replace
the disc.
25 2RY 0 0027
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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UNIT REPAIR (AW30–40LE) 7A4–61
4. Check direct clutch drum bushing.
Using a dial indicator, measure the inside diameter
of the clutch drum bushing.
Maximum inside diameter: 53.99 mm (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: J–25048
24 8RY 0 0002

7A4–62 UNIT REPAIR (AW30–40LE)
5. Install four plates and four discs.
Install in order : P–D–P–D–P–D–P–D
P : Plate, D : Disc
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6. Install the flange, with the flat side facing downward.
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7. Install the snap ring with a screwdriver.
Be sure the end gap of the snap ring is not aligned
with the cutout portion of the direct clutch drum.
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8. Check piston stroke of direct clutch (C–2).
Place the direct clutch assembly onto the OD
support assembly.
24 8RY 0 0029Using 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: 0.4 – 0.7 mm (0.016 – 0.028 in)
If the piston stroke is not within specification,
replace the discs and recheck the piston stroke.
If the piston stroke is nonstandard, select another
flange.

7A4–64 UNIT REPAIR (AW30–40LE)
Forward Clutch Asseembly (C-1)
Disassembled View
2 48R20 0003
E nd O FCallo ut
Legend
(1) Thrust bearing
(2) Race
(3) Snap ring
(4) Flange
(5) Disc and plate
Six discs and six plates
(6) Cushion plate(7) Snap ring
(8) Piston return spring
(9) Piston
(10) O-ring
(11) O-ring
(12 Oil seal ring
(13) Thrust bearing
(14) Forward clutch drum

UNIT REPAIR (AW30–40LE) 7A4–65
Disassembly
Remove forward clutch assembly from direct clutch
assembly.
24 8RY 0 003 9
1. Place wooden blocks, etc. to prevent forward clutch
shaft from touching the work stand, and place the
OD support on them.
Place the forward clutch onto the OD support and
remove the bearing and race.
24 8RY 0 004 8
2. Check piston stroke of forward clutch (C–1).
2 48R20 0008Using a dial indicator, measure the forward clutch
piston stroke by applying and releasing compressed
air (390 – 780 kPa or 57 – 114 psi) as shown.
Pack clearance: 0.5 – 0.9 mm (0.020 – 0.035 in)
3. Remove snap ring from clutch drum.
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4. Remove the flange, disc and plate, and cushion
plate.

7A4–66 UNIT REPAIR (AW30–40LE)
5. Place special tool on the spring retainer and
compress the return spring.
Using snap ring pliers, remove the snap ring.
Spring compressor : J–25048
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6. Remove the piston return spring.
7. Place the forward clutch drum onto the OD support.
Holding the forward clutch piston by hand, apply
compressed air to the OD support to remove the
forward clutch piston.
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8. Remove the O-rings from piston.
9. Remove the O-ring from forward clutch drum.
10. Remove the oil seal rings and thrust bearing from
forward clutch drum.
Inspection and Repair
1. Check forward 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.
24 8RY 0 0031
2. Check forward clutch drum bushing.
Using a dial indicator, measure the inside diameter
of the forward clutch drum bushing.
Maximum inside diameter: 24.08 mm (0.948 in)
If the inside diameter is greater then the maximum,
replace the forward clutch drum.
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3. Check disc, plate and flange.
Check to see if the sliding surface of the disc, plate
and flange are worn or burnt. If necessary, replace
them.
If the lining of the disc is peeling off or discolored,
or even if parts of the printed numbers are
defaced, replace all discs.

UNIT REPAIR (AW30–40LE) 7A4–67
Before assembling new discs, soak them in ATF
for at least fifteen minutes.
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4. Check piston return spring.
Using calipers, measure the free length of the return
spring.
Standard length: 19.47 mm (0.7665 in)
24 7RY 0 003 4
Reassembly
1. Coat the assembled thrust bearing and race with
petroleum jelly and install it onto the forward clutch
drum, with the race side facing downward.
Bearing and race (Reference)
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2. Coat the three oil rings with ATF.
Contract the oil seal rings as shown, and install
three oil seal rings onto the forward clutch drum.
NOTE: Do not spread the ring ends more than
necessary.
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Inside diameter 33.7 mm (1.327 in)
Outside diameter 47.8 mm (1.882 in)

7A4–68 UNIT REPAIR (AW30–40LE)
3. Coat a new O-ring with ATF and install O-ring on the
forward clutch drum.
24 8RY 0 004 7
4. Coat new O-rings with ATF and install two O-rings
on the forward clutch piston.
5. Being careful not to damage the O-rings, press the
forward clutch piston into the forward clutch drum.
24 8RY 0 004 9
6. Install piston return spring.
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7. Place special tool on the spring retainer, and
compress the return spring.
Spring compressor: J–25048
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.
24 8RY 0 0003