piston ISUZU TF SERIES 2004 Workshop Manual

UNIT REPAIR (AW30–40LE) 7A4–69
8. Install cushion plate rounded side down as shown.
24 8RY 0 006 9
9. Install five discs and five plates.
Install in order: P–D–P–D–P–D–P–D–P–D
10. And then install the flange, with the rounded edge
facing downward.
24 8RY 0 007 0
11. 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 forward clutch drum.
24 8RY 0 0041
12. Check piston stroke of forward clutch (C–1).
Using a dial indicator, measure the forward clutch
piston stroke by applying and releasing the
compressed air (380 – 780 kPa or 57 – 114 psi) as
shown.
Pack clearance: 0.5 – 0.9 mm (0.020 – 0.035 in)
If the piston stroke is not within specification,
replace the discs, and recheck the piston stroke.
Available flange sizes
2 48R20 0008
3.0 mm (0.118 in) 3.4 mm (0.134 in)
4.2 mm (0.165 in) 3.6 mm (0.142 in)
4.4 mm (0.173 in) 3.8 mm (0.150 in)
3.2 mm (0.126 in) 4.0 mm (0.158 in)

UNIT REPAIR (AW30–40LE) 7A4–77
Second Brake A ssembly (B–2)
Disassembled View
2 46R20 0001
E nd O FCallo ut
Disassembly
1. Remove second brake assembly from output shaft.
24 6RY 0 0007
Legend
(1) Second brake assembly
(2) Thrust washer (Plastic)
(3) Snap ring
(4) Spring retainer(5) Piston return spring
(6) Piston sleeve
(7) Second brake piston
(8) O-ring
(9) Second brake drum

7A4–78 UNIT REPAIR (AW30–40LE)
2. Remove the hrust washer (plastic).
3. Place special tool on the spring retainer, and
compress the return spring.
Spring compressor: J–25048
Remove the snap ring with snap ring pliers.
24 7RY 0 000 1
4. Remove the spring retainer and piston return spring.
5. Romove piston sleeve.
6. Holding the second brake piston by hand, apply
compressed air to the second brake drum to remove
the second brake piston.
Remove the second brake piston from the second
brake drum.
24 6RY 0 000 8
7. Remove the o-rings from the second brake piston.
Inspection and Repair
1. Check piston return spring.
Using calipers, measure the free length of the return
spring.
Standard length: 18.38 mm (0.724 in)
24 7RY 0 0034
Reassembly
1. Coat new O-rings with ATF and install them on the
second brake piston.
24 6RY 0 0009
2. Being careful not to damage the O-rings, press in
the second brake piston into the second brake
drum.
3. Install piston sleeve.

UNIT REPAIR (AW30–40LE) 7A4–79
4. Install piston return spring.
24 6RY 0 001 0
5. Install spring retainer.
6. 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 7RY 0 000 1
7. Check second brake piston movement.
Make sure the second brake piston moves smoothly
when applying and releasing the low compressed
air to the second brake drum.
24 6RY 0 0011
8. Coat the thrust washer (plastic) with petroleum jelly
and install it to the second brake piston, with the
grooved side facing upward.
NOTE: Make sure that the cutout portions of the thrust
washer match the teeth of the spring retainer.
24 6RY 0 0012

UNIT REPAIR (AW30–40LE) 7A4–87
First and Reverse Brake (B–3)
Disassembled View
24 6RY 0 0024
E nd O FCallo ut
Legend
(1) Thrust bearing and race
(2) Snap ring
(3) Piston return spring
(4) First and reverse brake piston No.2(5) O-ring
(6) Reaction sleeve
(7) O-ring
(8) First and reverse brake piston No.1
(9) O-ring

7A4–88 UNIT REPAIR (AW30–40LE)
Disassembly
1. Remove assembled thrust bearing and race from
transmission case.
24 7RY 0 004 3
2. Check first and reverse brake piston movement.
Make sure that first and reverse brake piston moves
smoothly when applying and releasing the
compressed air into the transmission case.
24 6RY 0 001 6
3. Set special tool on the spring retainer, and
compress the return spring.
Spring compressor: J–25048
Remove the snap ring with snap ring pliers.
24 7RY 0 0002
4. Remove the piston return spring.
5. Remove the first and reverse brake piston No.2.
Holding the first and reverse brake piston No.2 by
hand, apply compressed air to the transmission
case to remove the first and reverse brake piston
No.2.
Remove the first and reverse brake piston No.2.
If the piston does not pop out with compressed air,
lift the piston out with needle-nose pliers.
24 6RY 0 0016

UNIT REPAIR (AW30–40LE) 7A4–89
6. Remove the O-ring from first and reverse brake
piston No.2.
7. Remove the reaction sleeve.
Insert special tool behind the reaction sleeve and
gradually lift it out of the transmission case.
Reaction sleeve puller: J–37236
RUW 37A SH00 330 1
8. Remove the O-ring from reaction sleeve.
9. Remove the first and reverse brake piston No.1.
Insert special tool behind the first and reverse brake
piston No.1 and gradually lift it out of the
transmission case.
Piston puller: J–37237
RUW 37A SH00 340 1
10. Remove the O-rings from first and reverse brake
pistion No.1.
Reassembly
1. Coat three new O-rings with ATF.
Install the two O-rings on the No.1 piston.
2. Install the O-ring on the reaction sleeve.
3. Install the first and reverse brake piston No.1 to the
reaction sleeve.
24 6RY 0 0018
4. Coat a new O-ring with ATF and install it on the first
and reverse brake piston No.2.
5. Install the first and reverse brake piston No.1 with
reaction sleeve onto the first and reverse brake
piston No.2.
24 6RY 0 0019

7A4–90 UNIT REPAIR (AW30–40LE)
6. Align the teeth of the first and reverse brake piston
No.2 into the proper grooves.
Being careful not to damage the O-rings, press in
the first and reverse brake piston No.2 with No.1
into the transmission case.
24 6RY 0 002 0
7. Place piston return spring onto first and reverse
brake piston No.2.
24 6RY 0 002 1
8. Set special tool as shown, and compress the return
spring with special tool.
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 7RY 0 0002
9. Check first and reverse brake piston movement.
Make sure the first and reverse brake piston moves
smoothly when applying and releasing the
compressed air into the transmission case.
24 6RY 0 0022

7A4–132 UNIT REPAIR (AW30–40LE)
Special Tools
ILLUSTRATIONTOOL NO.
TOOL NAME
J–37227
Holding fixture
J–3289–20
Holding fixture base
J–37228
Oil pan seal cutter
J–23327–1
Spring compressor
J–9617
Oil seal installer; oil
pump
J–37233
Spring compressor; OD
brake piston
J–29770–A
Oil pressure gauge
J–25048
Spring compressor
J–37236
Reaction sleeve puller;
first and reverse brake
J–37237
Piston puller; first and
reverse brake
J–37232–2
Oil seal installer;
manual valve shaft seal
installer & remover
J–35467
Onennway clutch
testing tool; torque
converter ILLUSTRATIONTOOL NO.
TOOL NAME

7A1-8 CONSTRUCTION AND FUNCTION
STRUCTURE AND FUNCTION OF COMPONENT
TORQUE CONVERTER (WITH LOCK-UP FUNCTION)

The torque converter is a device for transmitting the engine torque to the transmission. It transmits power
by means of oil when the lock-up is disengaged and by means of a lock-up piston when it is engaged.

The torque converter is of the symmetrical, three-element, single-stage, two-phase type.

As shown in the drawing, the symmetrical three-elements refer to three elements (components) consisting
of impeller (1), turbine (2) and stator (3) that are arranged symmetrically (figure 5).

"Single-stage" means that there is only one turbine as an output element; "two-phase" means that the
pump impeller acts as a torque converter when the turbine speed is comparatively low, and as a fluid
coupling when the speed is high.


















1. Pump Impeller
2. Turbine Runner
3. Stator














1. Pump Impeller
2. Turbine Runner
3. Stator
4. Converter Cover
5. One-way Clutch
6. Lock-up Piston
7. Torsion Damper

Figure 5. Torque Converter
Figure 6. Construction of Torque Converter

Lock-up mechanism

"Lock-up" refers to a fixed state of the lock-up piston inside the torque converter and thus connects the
engine directly to the transmission.

The hydraulic pressure for the lock-up control is supplied from two circuits.

When the lock-up is disengaged (Figure 7)

When the lock-up is disengaged, the torque converter operating pressure is supplied from the oil passage
(A) to between the cover and the lock-up piston, and separates the lock-up piston clutch facing and
converter cover.

As a result, the engine drive power is transmitted from the converter cover to the pump impeller, the ATF
and to the turbine. The torque converter function as a fluid connector in this condition.

The torque converter operating pressure is supplied from the oil passage (A), passes through the oil
passage (B).

When the lock-up is engaged (Figure 8)

When the lock-up is engaged, the torque converter operating pressure is supplied from oil passage (B) to
the oil pump impeller, turbine, then to the stator side. The oil between the lock-up piston and converter
cover is drained.

Since the force acting on the right side of the lock-up piston is greater than force on the left side, it
connects the lock-up piston clutch facing with the converter cover, thereby increasing the transmission
efficiency.