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
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