AUTOMATIC TRANSMISSION

SECTION AT
CONTENTS
SERVICE DATA AND SPECIFICATIONS (SDS) ............2 Oil Passages from Control Valve Body to Main
General Specifications.................................................2 Shaft...........................................................................10
Inspection and Adjustment ..........................................3 OIL PRESSURE CIRCUIT DIAGRAM ..........................11
Tightening Torque ........................................................4 AUTOMATIC TRANSMISSION .....................................15
TROUBLE DIAGNOSES AND CORRECTIONS.............5 Construction...............................................................15
OIL CIRCUIT....................................................................8 Test ............................................................................20
Oil Passages from Oil Strainer to Control Valve Adjustment .................................................................22
Body.............................................................................8 SPECIAL SERVICE TOOLS..........................................24
 SERVICE DATA AND SPECIFICATIONS (SDS)

General Specifications
Torque converter

1-speed A/T
Type
Symmetrical, 3-element, 1-stage, 2-phase torque converter

Model D01 D02

Engine H20-II TD27 H25 TD27

NF27L NF27H NF27H NF27H

Stall torque ratio
3.2 : 1 2.8 : 1 2.8 : 1 2.8 : 1

Transmission

Type 1-speed forward and 1-speed reverse, constant-mesh

Clutch Multi-disc clutch

Number of drive plate

Forward 6

Reverse 6

Number of driven plate

Forward 6

Reverse 6
LOW NOISE LOW NOISE
Gear ratio STD OPTION STD OPTION

Forward
3.105 3.105 2.762 3.105 3.105 2.762
Reverse

Oil pump

Type Internally intermeshing involute gear pump

Automatic transmission fluid DEXRONTM or M2C-33E or F

Lubrication system Forced lubrication by oil pump

Cooling system Water-cooled by oil cooler

TB-DX-AT-0501 AT-2 JUNE 2005

 SERVICE DATA AND SPECIFICATIONS (SDS)

Inspection and Adjustment

TORQUE CONVERTER
Unit: mm (in) OIL PUMP
Unit: mm (in)
Lateral runout of drive plate
Standard Service limit
Standard 0.2 (0.008)
Side clearance of oil 0.02 - 0.04
Service limit 0.5 (0.020) 0.08 (0.0031)
pump gear (0.0008 - 0.0016)
OD of oil seal contacting portion of 41.915 - 41.965
Clearance between
sleeve (1.6502 - 1.6522) 0.14 - 0.21
outer gear and cres- 0.25 (0.0098)
(0.0055 - 0.0083)
cent
TRANSMISSION Clearance between
Unit: mm (in) 0.05 - 0.20
outer gear and hous- 0.25 (0.0098)
(0.0020 - 0.0079)
ing
Width of groove of mainshaft servo
ring

2.26 - 2.29
LINE PRESSURE
Standard Unit: kPa (bar, kg/cm2, psi)
(0.0890 - 0.0902)

Service limit 2.40 (0.0945) 883 - 1,079

Main line pressure (8.8 - 10.8, 9 - 11, 128 - 156)
Width of servo ring at 1,000 rpm or over
2.11 - 2.16 883 - 1,079
Standard Forward and reverse clutch oil
(0.0831 - 0.0850) (8.8 - 10.8, 9 - 11, 128 - 156)
pressure
Service limit 2.07 (0.0815) at 1,000 rpm or over

Thickness of drive plate 196 - 392

Converter inlet pressure (2.0 - 3.9, 2 - 4, 28 - 57)
2.5 - 2.65 at 1,000 rpm or over
Standard
(0.0984 - 0.1043)

Service limit 2.2 (0.087) ENGINE STALL REVOLUTION

Thickness of driven plate Unit: rpm

1.5 - 1.7 Stall revolution

Standard
(0.059 - 0.067)
H20-II 2,350 - 2,550
Service limit 1.4 (0.055)
H25 1,900 - 2,100
Clearance between retaining plate
TD27 1,850 - 2,050
and snap ring

1.8 - 2.4
Standard
(0.071 - 0.094)
OIL CAPACITY
Unit:  (Imp qt)
Limit 6.5 (0.256)
Oil capacity in transmission case 5.5 (4-7/8)
0.10 - 0.15
Backlash of each gear Oil capacity in torque converter 2.5 (2-1/4)
(0.0039 - 0.0059)

AT-3
 SERVICE DATA AND SPECIFICATIONS (SDS)

Tightening Torque

ATM0101

: N⋅m (kg-m, in-lb) : N⋅m (kg-m, ft-lb)

: 9.2 - 11.7 (0.93 - 1.2, 81 - 104) : 16 - 20 (1.6 - 2.1, 12 - 15)
: 3.8 - 5.0 (0.38 - 0.51, 33 - 44) : 30 - 40 (3.1 - 4.1, 22 - 30)
: 275 - 343 (28 - 35, 203 - 253)
: 76 - 98 (7.8 - 10.0, 56 - 72)
: 246 - 294 (25 - 30, 181 - 216)
: 89 - 118 (9.1 - 12.0, 66 - 87)
: 78 - 98 (8 - 10, 58 - 72)

AT-4
 TROUBLE DIAGNOSES AND CORRECTIONS

Condition Probable cause Corrective action

Low output Torque converter

I Low oil pressure

(1) Insufficient oil quantity Add oil.

(2) Air sucked from suction side Retighten or change packing.

(3) Clogged oil filter Clean or replace.

(4) Worn oil pump (low discharge) Replace.

(5) Fatigue of regulator valve coil spring Replace.

(6) Malfunction of regulator valve spool Repair or replace.

(7) Worn piston ring or O-ring Replace.

I Brake in stator free wheel cam Replace torque converter assembly.

I Seize stator free wheel Replace torque converter assembly.

I Broken blades or interference of blade Replace torque converter assembly.

Transmission

I Use of improper oil or air bubbles

(1) Air sucked from suction side Replace.

Retighten or change packing.

(2) Air bubbles due to too low torque converter Adjust.

pressure
(3) Water in oil Change oil.

I Improper position of brake shift spool and link lever Adjust.

I Slippery clutch

(1) Low main pressure Replace oil pump, control valve.

(2) Wear on piston ring or O-ring Replace.

(3) Break in clutch piston Replace.

(4) Seizure or drag of clutch plate Replace.

I Solenoid valve
Broken solenoid valve, foreign objects or dirt, or Replace solenoid valve assembly.
poor electrical power

Unusual rise of oil temperature Torque converter

I Improper oil quantity Add or reduce oil.

I Clogged oil filter (insufficient circulating quantity) Clean or replace.

I Interference of wheel vane Replace torque converter assembly.

I Faulty stator free wheel Replace torque converter assembly.

I Air sucked into system. Retighten or change gasket.

I Water oil tank or transmission case Change oil.

I To large resistance in piping (insufficient circulating Repair or replace.

quantity)
I Worn or seize bearing Repair or replace.

I Faulty instrument Replace.

Transmission

I Dragging of clutch Replace clutch plate or solenoid valve assembly.

I Faulty instrument Replace.

I Worn or seized bearing Replace.

AT-5
 TROUBLE DIAGNOSES AND CORRECTIONS

Condition Probable cause Corrective action

Noisy operation Torque converter

I Break in drive plate Replace drive plate.

I Worn or faulty bearing Replace torque converter assembly.

I Interference of vane wheel Replace torque converter assembly.

I Loose bolt Retighten or replace.

I Worn spline Replace torque converter assembly.

I Noise in gear pump Repair or replace.

Transmission

I Dragging of clutch due to seizure Replace clutch plate.

I Worn or seized bearing Replace.

I Break in gear Replace.

I Loose bolt Retighten or replace.

I Worn spline Replace.

I Cavitation caused by clogged strainer Clean or replace.

Unusual main pressure/torque Too high pressure

converter oil pressure
I Clogged oil filter (outlet side) Clean.

I Malfunction of regulator valve Repair or replace valve.

Clean or repair.

I Too large resistance in piping Repair.

I Cold weather (when high viscosity oil is used) Repair.

I Faulty instrument Replace.

I Use of improper oil Change oil.

Too low pressure

I Faulty gear pump (wear) Replace.

I Excessive oil leak

(1) Faulty regulator valve coil spring Replace.

(2) Faulty regulator valve spool Repair or replace valve.

(3) Faulty modulator valve coil spring Replace.

I Air is sucked into system. Retighten or change packing.

I Insufficient oil Add.

I Clogged oil filter Clean or replace.

Transmission

I Excessive oil leak Replace.

I Faulty instrument Replace.

I Solenoid valve

Broken solenoid valve, foreign objects or dirt, or Replace solenoid valve assembly.
poor electrical power

AT-6
 TROUBLE DIAGNOSES AND CORRECTIONS

Condition Probable cause Corrective action

Oil leak from torque converter/ I Oil leak from oil seal Replace oil seal. Replace pump boss, coupling, etc.
transmission/solenoid valve
I Oil leak from jointing surfaces of case Retighten bolts or change packing.

I Oil leak from joint or pipe Repair or replace pipe gasket.

I Oil leak from drain plug Retighten or replace gasket.

I Cracks or blow holes Repair or replace.

I Flowing out of oil from transmission case and tank Change oil.
Retighten or replace packing.

I Leakage from the solenoid valve seal Replace O-ring and gasket.

I Leakage from the solenoid valve Replace solenoid valve assembly if necessary.

I Excessive oil Reduce oil.

No transmission of power Torque converter

I Break in drive plate Replace.

I Insufficient oil Add oil.

I Faulty oil pump driving system Replace.

I Broken shaft Replace.

I No oil pressure Replace.

Transmission

I Insufficient oil Add oil.

I Improper location of inching spool and link lever Adjust.

I Improper location of forward/reverse spool and link Adjust.
lever

I Clutch acting in both directions

(1) Faulty piston ring of servo case Replace.

(2) Clutch seizure/deformation Replace.

(3) Broken conical plate Replace.

I Seized clutch Replace.

I Broken shaft Replace.

I Break in clutch drum (snap ring groove) Replace.

I Broken snap ring for clutch drum Replace.

I Foreign matter caught in oil passage to clutch Clean or replace.

I Worn shaft spline Replace.

Solenoid valve
I Broken solenoid valve, foreign objects or dirt, or poor Replace solenoid valve assembly.
electrical power

AT-7
 OIL CIRCUIT

Oil Passages from Oil Strainer to Control Valve

Body

ATM0102

ATM0103

AT-8
 OIL CIRCUIT
Oil Passages from Oil Strainer to Control Valve
Body (Cont’d)

ATM0104

ATM0105

AT-9
 OIL CIRCUIT

Oil Passages from Control Valve Body to Main

Shaft

ATM0106

ATM0107

AT-10
 OIL PRESSURE CIRCUIT DIAGRAM

NEUTRAL RANGE

ATM0108

AT-11
 OIL PRESSURE CIRCUIT DIAGRAM

FORWARD RANGE

ATM0109

AT-12
 OIL PRESSURE CIRCUIT DIAGRAM

REVERSE RANGE

ATM0110

AT-13
 OIL PRESSURE CIRCUIT DIAGRAM

INCHING

ATM0111

AT-14
 AUTOMATIC TRANSMISSION

Construction

ATM0112

q
1 Drive cover q
10 Reverse gear q
19 Orifice
q
2 Turbine runner q
11 Control valve q
20 Drive pinion shaft
q
3 Stator q
12 Clutch piston q
21 Pinion shaft spacer
q
4 One-way clutch q
13 Return spring q
22 Reduction gear
q
5 Pump impeller q
14 Clutch drum q
23 Bearing cover
q
6 Oil pump sleeve q
15 Forward gear q
24 Idler gear
q
7 Oil pump housing q
16 Servo case q
25 Idler shaft
q
8 Oil pump cover q
17 Needle bearing q
26 Solenoid valve
q
9 Main shaft q
18 Oil pump

AT-15
 AUTOMATIC TRANSMISSION
Construction (Cont’d)
TRANSMISSION

ATM0113

AT-16
 AUTOMATIC TRANSMISSION
Construction (Cont’d)
OIL PUMP AND TORQUE CONVERTER

ATM0114

CONTROL VALVE

ATM0115

q
1 Inching valve q
5 Relief valve q
8 Check valve
q
2 Regulator valve q
6 Modulator spring q
9 Check spring
q
3 Regulator spring q
7 Modulator piston q
10 Modulator plug
q
4 Side plate

AT-17
 AUTOMATIC TRANSMISSION
Construction (Cont’d)
SOLENOID VALVE

ATM0116

q
1 Body q
8 Pin q
14 Stopper
q
2 Spool q
9 Solenoid coil q
15 Plug
q
3 Plug q
10 Bolt q
16 Tube
q
4 Pin q
11 O-ring q
17 Plunger
q
5 Spring q
12 O-ring q
18 O-ring
q
6 Retainer A q
13 O-ring q
19 Snap ring
q
7 Retainer B
Specifications
Applied voltage V 10 - 15
Oil temperature °C (°F) −30 to 130 (−22 to 266)
Coil resistance Ω/°C (°F) 5.4/20 (68)

ATT0132

AT-18
 AUTOMATIC TRANSMISSION
Construction (Cont’d)
Forward solenoid (SOL.a) and reverse solenoid (SOL.b) are as
figure.
The SOL.a lead-wire is white and the SOL.b lead-wire is black.

ATM0123

Inspection
Inspection item Factory-set value Service limits Out-of-limits countermeasure
Coil wire is cut or shorted.
5.4Ω±5% 5.4Ω±10%
Coil resistance Replace the solenoid valve
[20°C (68°F)] [20°C (68°F)]
assembly.
Coil insulation is bad. Replace
Coil insulation resistance More than 100 MΩ 10 MΩ
the solenoid valve assembly.
Replace the O-ring on the sole-
Oil leaking from solenoid valve — Oozing out
noid valve.

Troubleshooting
Trouble symtoms Possible cause Corrective action
Solenoid valve dose not operate properly. Foreign object is caught in the spool. 1. Check continuity.
a. When the solenoid valve is energized, I The solenoid valve should be installed
the spool is not changed over and so to the transmission assembly.
the power is not transmitted to the 2. When it does not operate properly, push
vehicle. the pin q5 several times with your
b. When the current to the solenoid valve fingers, then check the continuity again.
is cut off, the spool is not changed over When it operates properly, go to step 8.
and so the power to the vehicle is not 3. When it does not operate properly,
turned off. remove the solenoid valve body from
the transmission assembly; then per-
form steps 4 to 8 below.
4. Blow air from the port hole to the spool
q4 .
5. Push the pin q 5 several times, then
check the continuity.
I At this time, visually check thet the
spool q4 can move from the port hole.
6. When it operwte properly, install it to
the transmission assembly, then check
the continuity.
7. When it does not operate properly,
replace the solenoid valve as an
assembly.
8. By changing over the solenoid valve
sevaral times, check that the solenoid
valve operates properly.
I Pushing pressure of pin q 5 = approx. 10
- 29 N (1 - 3 kg, 2 - 7 lb)
I Before performing the steps shown
above, be sure to take safety measures
such as jacking up the front wheels, etc.

AT-19
AUTOMATIC TRANSMISSION

Test
LINE PRESSURE TEST
Tools and equipment
I Oil pressure gauge assembly
(with adapters)
ST0221S000
I Engine tachometer
I Wrench
I Sealing tape
I Chock
Test procedures
1. Before testing, check coolant, engine oil and torque converter
oil; warm up torque converter oil to operating temperature.
2. Secure front and rear wheels with chocks and apply hand
brake.
3. Remove blind plug and connect oil pressure gauge to its open-
ing.
4. Mount engine tachometer.
5. Measure clutch oil pressure while engine is running more than
1,000 rpm with gears shifted into Forward or Reverse position.
6. Measure torque converter oil pressure while engine is running
more than 1,000 rpm.
If oil pressure builds up in the FORWARD (or the REVERSE)
position, shift gears to the REVERSE (or the FORWARD) posi-
tion. Oil pressure should drop to zero upon gearshifting.
Unit: kPa (bar, kg/cm2, psi)

883 - 1,079
Main line pressure (8.8 - 10.8, 9 - 11, 128 - 156)
at 1,000 rpm or over

883 - 1,079
Forward and reverse clutch oil pressure (8.8 - 10.8, 9 - 11, 128 - 156)
at 1,000 rpm or over

196 - 392
Converter inlet pressure (2.0 - 3.9, 2 - 4, 28 - 57)
at 1,000 rpm or over

ATM0117

AT-20
AUTOMATIC TRANSMISSION
Test (Cont’d)
STALL TEST
The purpose of this test is to check for transmission and engine
malfunction by measuring the maximum engine rpm while truck is
in a stalled condition. The carburetor should be at full throttle with
selector lever in position “F” and “R” respectively. Compere mea-
sured values with standard values.
Tools and equipment
I Engine tachometer
I Chock
Test procedures
1. Before testing, check coolant, engine oil and torque converter
oil; warm up torque converter oil to operating temperature.
2. Mount engine tachometer in a location visible from operator’s
seat.
3. Secure front and rear wheels with chocks and apply hand
brake. Be sure to depress brake pedal firmly with the left foot
before depressing accelerator pedal. Do not depress inching
brake pedal.
4. Throw selector lever into position “F”.
5. Slowly depress accelerator pedal until throttle valve is fully
open.
Quickly read and record engine rpm when engine begins to
rotate steadily and then release accelerator pedal.
Engine stall speed:
H20-II 2,350 - 2,550 rpm
H25 1,900 - 2,100 rpm
TD27 1,850 - 2,050 rpm
6. Shift selector lever to neutral and run engine at approximately
1,500 rpm for more than one minute to cool down torque con-
verter oil and coolant.
7. Make similar stall test in position “R”.
CAUTION:
The stall test operation specified in item (5) should be made
within 30 seconds. If it takes too long, oil deteriorates and
clutches are adversely affected. Sufficient cooling time should
be given between tests.

AT-21
 AUTOMATIC TRANSMISSION

Adjustment
INCHING CONTROL

ATM0119

1. Adjust inching-brake pedals’ height “H” to the specified value

with pedal stopper bolt.
Inching-brake pedals’ height “H”:
105 - 115 mm (4.13 - 4.53 in)
Inching pedal stopper lock nut:
: 16 - 20 N⋅m (1.6 - 2.1 kg-m, 12 - 15 ft-lb)

AT-22
 AUTOMATIC TRANSMISSION
Adjustment (Cont’d)

ATM0118

2. Adjust clearance between contact bolt and inching brake pedal.

Clearance:
4.4 - 5.7 mm (0.173 - 0.224 in)
Contact bolt lock nut:
: 19 - 26 N⋅m (1.9 - 2.7 kg-m, 14 - 19 ft-lb)

ATM0120

3. Turn the inching lever ( ) on the transmission side in the direc-

tion of the arrow until it locks.
4. Adjust the inching cable in this state, and tighten the lock nut.

AT-23
 SPECIAL SERVICE TOOLS

Tool number
Description
Tool name
KV31101400
Clutch spring compressor

NT793

ST0221S000
Oil pressure gauge

NT794

AT-24
 ne00479 Pagina 1 6-7-2005
Technical Bulletin

Issue : TB-DX-AT-0501
Date : June 2005

Applied Model : DX SERIES

Applied From : Production in June, 2005

Subject : DX MINOR CHANGE

Introduction:
As of June 2005, the DX series will have several design changes, amongst others a
new finger tip lever and a low noise option. Because of these design changes, the
following pages in the AT section have been added.

”AT ”section
- Page AT-2-1

The information in this bulletin should not be interpreted as basis for claims, unless so designated.
Whenever you order parts, refer to the parts bulletin, not to this Technical Bulletin

TB-DX-AT-0501 Page 1 June 2005

 SERVICE DATA AND SPECIFICATIONS (SDS)

General Specifications
Torque converter

1-speed A/T
Type
Symmetrical, 3-element, 1-stage, 2-phase torque converter

Model D01 D02

Engine H20-II TD27 H25 TD27

NF27L NF27H NF27H NF27H

Stall torque ratio
3.2 : 1 2.8 : 1 2.8 : 1 2.8 : 1

Transmission

Type 1-speed forward and 1-speed reverse, constant-mesh

Clutch Multi-disc clutch

Number of drive plate

Forward 6

Reverse 6

Number of driven plate

Forward 6

Reverse 6
LOW NOISE LOW NOISE
Gear ratio STD OPTION STD OPTION

Forward
3.105 3.105 2.762 3.105 3.105 2.762
Reverse

Oil pump

Type Internally intermeshing involute gear pump

Automatic transmission fluid DEXRONTM or M2C-33E or F

Lubrication system Forced lubrication by oil pump

Cooling system Water-cooled by oil cooler

TB-DX-AT-0501 AT-2-1 JUNE 2005