Toyota Automatic Transmission A340 Series. Repair Manual - part 3

SENSORS

ACTUATORS

ELECTRONIC CONTROL SYSTEM

(A340E, A340F)

The electronic control system, which controls the shift points and the operation of the lock−up clutch, is

composed of the following three parts:

1.

Sensors
These sensors sense the vehicle speed, throttle opening and other conditions and send these

data to the ECU in the form of electrical signals.

2.

ECU
The ECU determines the shift and lock−up timing based upon the signals from sensors, and

controls the solenoid valves of the hydraulic control unit accordingly.

3.

Actuators
These are three solenoid valves that control hydraulic pressure acting on the hydraulic valves

to control shifting and lock−up timing.

ECU

DRIVING  PATTERN

SELECTOR

Control of shift

timing

NO. 1

SOLENOID  VALVE

NEUTRAL  START

SWITCH

NO. 2

SOLENOID  VALVE

THROTTLE  POSITION

SENSOR

Control of lock−

up timing

LOCK−UP

SOLENOID  VALVE

VEHICLE  SPEED

SENSOR

BRAKE LIGHT SWITCH

O/D OFF

INDICATOR  LIGHT

Self−diagnostic

system

O/D MAIN SWITCH

CRUISE  CONTROL

ECU

Back−up system

WATER  TEMPERA-

TURE SENSOR

−

AUTOMATIC TRANSMISSION

Operation

AT−13

ND0045

Transfer Rear Output Shaft

C

4

B

4

Chain

C

3

Transmission Output Shaft

Transfer Planetary Gear Unit

Transfer gear position

No. 4 solenoid valve

C

3

C

4

B

4

H2

OFF

F

H4

OFF

F

F

L4

ON

F

F

AT2157

Front Planetary

Gear Unit

F

1

O/D Input

Shaft

F

2

Output Shaft

B

2

C

2

B

0

B

3

C

1

Rear Planetary Gear Unit

B

1

C

0

F

0

O/D Planetary

Gear Unit

Input

Shaft

Range (i.e.,

Shift Lever

Position)

Gear

No. 1

Solenoid

Valve

No. 2

Solenoid

Valve

C

0

C

1

C

2

B

0

B

1

B

2

B

3

F

0

F

1

F

2

I.P.

O.P.

P

Parking

ON

OFF

F

R

Reverse

ON

OFF

F

F

F

F

F

N

Neutral

ON

OFF

F

D

1st

ON

OFF

F

F

F

F

2nd

ON

ON

F

F

F

F

F

3rd

OFF

ON

F

F

F

F

F

O/D

OFF

OFF

F

F

F

F

2

1st

ON

OFF

F

F

F

F

2nd

ON

ON

F

F

F

F

F

F

3rd

OFF

ON

F

F

F

F

F

L

1st

ON

OFF

F

F

F

F

F

F

* 2nd

ON

ON

F

F

F

F

F

F

OPERATING CONDITIONS

(A340H)

1.

Transmission

* Down−shift only in the L range and 2nd gear − no up−shift.

I.P. ....... Inner Piston

O.P. ..... Outer Piston

2.

Transfer

AT−14

−

AUTOMATIC TRANSMISSION

Operation

Component

Function

C

1

Forward Clutch

Connects input shaft and front planetary ring gear.

C

2

Direct Clutch

Connects input shaft and front & rear planetary sun gear.

C

0

O/D Direct Clutch

Connects overdrive sun gear and overdrive planetary carrier.

B

1

2nd Coast Brake

Prevents front & rear planetary sun gear from turning either clockwise or counterclockwise.

B

2

2nd Brake

Prevents outer race of F

1

 from turning either clockwise or counterclockwise thus

preventing the front & rear planetary sun gear from turning counterclockwise.

B

3

1st & Reverse Brake

Prevents rear planetary carrier from turning either clockwise or counterclockwise.

B

0

O/D Brake

Prevents overdrive sun gear from turning either clockwise or counterclockwise.

F

1

No. 1 One−Way Clutch

When B

2

 is operating, this clutch prevents the front & rear planetary sun gear from turning

counterclockwise.

F

2

No. 2 One−Way Clutch

Prevents rear planetary carrier from turning counterclockwise.

F

0

O/D One−Way Clutch

When the transmission is being driven by the engine, this clutch connects the overdrive sun

gear and overdrive planetary carrier.

Planetary Gears

These gears change the route through which driving force is transmitted in accordance

with the operation of each clutch and brake in order to increase or reduce the input and

output speed.

AT5440

Front & Rear Sun Gear

O/D Input

Shaft

Front Ring Gear

Rear Ring Gear

O/D Sun Gear

Output Shaft

Input Shaft

OUT

O/D Ring Gear

Rear Carrier

Rear Pinion

Front

Pinion

O/D Pinion

O/D Carrier

Front Carrier

IN

FUNCTION OF COMPONENTS

(A340H)

1.

Transmission

−

AUTOMATIC TRANSMISSION

Operation

AT−15

AT5854

D or 2 Range 1st Gear

AT5854

2 or L Range 2nd Gear

AT5854

D Range 2nd Gear

AT5854

L Range 1st Gear

AT5854

D or 2 Range 3rd Gear

AT5854

R Range Reverse Gear

AT5854

D Range O/D

FUNCTION OF COMPONENTS (Cont’d)

The conditions of operation for each gear position are shown in the following illustrations:

C

0

C

0

C

0

C

0

C

0

C

0

C

1

C

1

C

1

C

1

C

1

C

1

C

2

C

2

C

2

B

0

B

2

B

2

B

2

B

2

B

3

B

3

B

1

AT−16

−

AUTOMATIC TRANSMISSION

Operation

Component

Function

C

3

Forward Clutch

Connects transmission output shaft and transfer pinion gear.

C

4

Direct Clutch

Connects transfer rear output shaft and front drive gear.

B

4

O/D Direct Clutch

Prevents transfer ring gear from turning either clockwise or counterclockwise.

ND0047

Transfer Front

Output Shaft

Chain

Ring Gear Front Drive Gear

OUT

Transfer Rear Output Shaft

OUT

Transmission

Output Shaft

IN

ND0047

H2 Range

ND0047

H4 Range

ND0047

L4 Range

FUNCTION OF COMPONENTS (Cont’d)

2.

Transfer

The conditions of operation for each gear position are shown in the following illustrations:

B4

C

3

C

3

C

4

C

4

−

AUTOMATIC TRANSMISSION

Operation

AT−17

VALVE BODY

HYDRAULIC CONTROL SYSTEM

(A340H)

1.

Transmission

The hydraulic control system is composed of the oil pump, the valve body, the solenoid valves, and the

clutches and brakes, as well as the fluid passages which connect all of these components. Based on the

hydraulic pressure created by the oil pump, the hydraulic control system governs the hydraulic pressure

acting on the torque converter, clutches and brakes in accordance with the vehicle driving conditions.

There are three solenoid valves on the valve body. These solenoid valves are turned on and off by sig-

nals from the Engine & ECT ECU to operate the shift valves. These shift valves then switch the fluid

passages so that fluid goes to the torque converter and planetary gear units.

HYDRAULIC CONTROL SYSTEM

Hydr. pressure control

OIL PUMP

CLUTCHES & BRAKES

Fluid passage switching

Planetary gear sets

Torque converter

SOLENOID VALVES

ECU

2.

Transfer

The hydraulic control system consists of a valve body, No. 4 solenoid valve, a brake (B

4

) and two

clutches (C

3

, C

4

) and passages that connect these elements. It hydraulically controls the planetary gear

unit either manually, or automatically by the Engine & ECT ECU.

AT−18

−

AUTOMATIC TRANSMISSION

Operation

ACTUATORS

SENSORS

ELECTRONIC CONTROL SYSTEM

(A340H)

The electronic control system, which controls the transmission and transfer shift timing and the operation

of the lock−up clutch, is composed of the following three parts:

1.

Sensors
These sensors sense the vehicle speed, throttle opening and other conditions and send these data

to the Engine & ECT ECU in the form of electrical signals.

2.

Engine & ECT ECU
The Engine & ECT ECU determines the transmission and transfer shift timing and lock−up timing

based upon the signals from sensors, and controls the solenoid valves of the hydraulic control unit

accordingly.

3.

Actuators
These are four solenoid valves that control hydraulic pressure acting on the hydraulic valves to

control shifting and lock−up timing.

Engine & ECT ECU

DRIVING PATTERN

SELECTOR

NO. 1

SOLENOID VALVE

Control of

transmission

shift timing

NO. 2 SOLENOID

VALVE

NEUTRAL START

SWITCH

Control of

lock−up timing

LOCK UP SOLENOID

VALVE

TRANSFER SHIFT

POSITION SWITCH

NO. 4

SOLENOID VALVE

THROTTLE POSITION

SENSOR

Control of transfer

shift timing

VEHICLE SPEED

SENSOR

Self−diagnostic

system

BRAKE LIGHT SWITCH

Back−up system

O/D OFF INDICATOR

LIGHT

O/D MAIN SWITCH

A.T. OIL TEMP.

WARNING LIGHT

Fluid temperature

warning system

CRUISE CONTROL

ECU

WATER TEMPERATURE

SENSOR

FLUID TEMPERATURE

SENSOR

−

AUTOMATIC TRANSMISSION

Operation

AT−19

Illustration

Part No.

Part Name

Note

09032−00100

Oil Pan Seal

Cutter

09043−38100

Hexagon 10 mm

Wrench

Transfer (A340F)

09201−60011

Valve Guide Bushing

Remover & Replacer

Transfer (A340F)

09223−15010

Crankshaft Front

Oil Seal Replacer

Transfer (A340F)

09223−22010

Crankshaft Front

Oil Seal Replacer

Transfer (A340F)

09240−00020

Wire Gauge Set

09304−12012

Input Shaft Front

Bearing Replacer

Transfer (A340F)

09308−00010

Oil Seal Puller

09313−30021

Detent Ball Plug

Socket

Transfer (A340F)

09316−60010

Transmission &

Transfer Bearing

Replacer

Transfer (A340F)

(09316−00010)

Replacer ”A”

Transfer (A340F)

(09316 − 00070)

Replacer ”F”

Transfer (A340F)

09320−89010

Transfer Clutch

Spring Compressor

A340H

09330−00021

Companion Flange

Holding Tool

A340H

PREPARATION

SST (SPECIAL SERVICE TOOLS)

AT−20

−

AUTOMATIC TRANSMISSION

Preparation