1. Final gear
2. Differential gear assembly
3. Counter shaft
4. 1st and reverse brake
5. Counter driven gear11. Forward clutch
12. Direct clutch
13. Input shaft
14. Torque converter
15. Oil pump 6. Output shaft
7. Rear planetary gear
8. Front planetary gear
9. Valve body assembly
10. Oil strainer
AUTOMATIC TRANSMISSION (3 A / T) (VEHICLE WITH WU-TWC) 7B-3
GENERAL DESCRIPTION
The automatic transmission consists of the hydraulic torque converter, electronically controlled 3-speed automatic
transmission, countershaft and differential.
The transmission consists of 2 planetary gears, 2 disk clutches, 1 band brake, 1 disk brake and 1 one-way clutch.
Its operation is controlled by selecting a position from 6 positions (P, R, N, D, 2 and L ranges) manually by means
of the selector lever installed on the compartment floor.
In the D or 2 range, the gear ratio is changed for the 1st, 2nd or 3rd speed (D range only) automatically by engine
control module (electronic control).
For the automatic transmission fluid, DEXRON
-E, DEXRON- or its equivalent must be used. Lubrication
in the automatic transmission is provided by the oil pump which is operated by the engine revolution. Therefore,
the engine should not be stopped even during coasting to obtain proper lubrication.
When it becomes necessary to be towed, front wheels must be raised so as not to roll them.
1. Transmission range sensor
2. Select cable
1. Transmission
2. Shift solenoid-B
(No.2, 2nd brake solenoid valve)
3. Shift solenoid-A
(No.1, direct clutch solenoid valve)
4. Oil strainer
7B-8 AUTOMATIC TRANSMISSION (3 A / T) (VEHICLE WITH WU-TWC)
TRANSMISSION RANGE SENSOR (SHIFT SWITCH)
Being linked with the selector lever, this sensor changes selector
lever positions into electric signals and send them to the engine
control module. The contact points of this sensor for P and N ranges
are also connected with the starting motor circuit.
So when the selector lever is shifted to the P or N range position,
the contact points for P or N range are connected and cause the
starting motor to operate by turning the starter switch ON.
When the selector lever is in any other position than P and N
ranges, the sensor remains OFF and therefore the starting motor
cannot be operated, that is, the engine cannot be started.
Also, as its contact point for R range is connected with the backup
lamp circuit, only when the selector lever is shifted to R range, the
contact point contacts to light the backup lamp.
DIRECT CLUTCH AND 2ND BRAKE SOLENOID
VALVES
These solenoid valves are mounted on the valve body. They are
turned ON and OFF by the signals from the engine control module
and actuate each shift valve (1 – 2 and 2 – 3 valves) so as to control
transmission gear shift.
Shift solenoid-B (2nd brake solenoid valve) operates 1 – 2 shift
valve, and shift solenoid-A (direct clutch solenoid valve) does 2 –
3 shift valve.
OPERATION OF DIRECT CLUTCH AND 2ND BRAKE SOLENOIDS
RangeD2LP, N & R
Gear1st2nd3rd1st2nd1st(2nd)–
Shift solenoid-A (No.1)
(Direct clutch solenoid valve)
Shift solenoid-B (No.2)
(2nd brake solenoid valve)
: Operated (Solenoid Valve is Open): Unoperated (Solenoid Valve is Closed)
1. Countershaft gear
2. Output shaft speed sensor
A: Magnetic core end
D or 2
1→2
18
11
52
33D
2→3
33
21
97
613→2
14
9
82
51D or 2
2→1
14
9
37
23L
2→1
37
23
37
23 Full close
Full openkm / h
mile/h
km / h
mile/h Throttle SpeedGear Selector
VEHICLE SPEED
UpshiftDownshift
THROTTLE VALVE OPENING
[G10 Engine Model]
AUTOMATIC TRANSMISSION (3 A / T) (VEHICLE WITH WU-TWC) 7B-9
OUTPUT SHAFT SPEED SENSOR (A / T VSS)
The output shaft speed sensor consists of a magnetic core with
magnet and coil. It is mounted on transmission case with 0.6 mm
(0.024 in.) air gap between the core end and countershaft gear
tooth.
While the countershaft rotates, magnetic flux is cut by gear tooth
thus a pulse is generated in the sensor coil according to the speed.
And then, the pulse is transmitted to engine control module as
speed signal.
AUTOMATIC SHIFT DIAGRAM
Automatic shift schedule as a result of shift control is shown below. In case that selector lever is shifted to L range
at a higher than 37 km / h (23 mile / h) (G10 engine model), 40 km / h (25 mile / h) (G13 engine model) speed, 2nd
gear is operated and then down shifts to 1st at a speed lower than that. No up shift is available in L range.
7B-18 AUTOMATIC TRANSMISSION (3 A / T) (VEHICLE WITH WU-TWC)
VISUAL INSPECTION
Visually check following parts and systems.
INSPECTION ITEM
REFERRING SECTION
A / T fluid– – – – – level, leakage, color
A / T fluid hoses – – – – – disconnection, looseness, deterioration
Throttle cable – – – – – play, installation
A / T oil pressure control cable and select cable – – – – – installation
Engine oil – – – – – level, leakage
Engine coolant – – – – – level, leakage
Battery – – – – – fluid level, corrosion of terminal
Connectors of electric wire harness – – – – – disconnection, friction
Fuses – – – – – burning
Parts – – – – – installation, bolt – – – – – looseness
Parts – – – – – deformation
Other parts that can be checked visually
Also check following items at engine start, if possible.
Malfunction indicator lamp
Charge warning lamp
Engine oil pressure warning lamp
Engine coolant temp. meter
Other parts that can be checked visuallySection 0B
Section 7B
Section 6E1 or 6E2
Section 7B
Section 0B
Section 0B
Section 6 or 6-1
Section 8
Section 6 or 6-1
Section 6H
Section 8 (Section 6A or 6A1 for
pressure check)
ACCEPTABLE RANGE
1st gear (solenoids ON and ON)
2nd gear
(solenoids ON and OFF)
3rd gear
(solenoids OFF and OFF)
Vehicle speed
Engine speed
7B-28 AUTOMATIC TRANSMISSION (3 A / T) (VEHICLE WITH WU-TWC)
DTC P0751 SHIFT SOLENOID-A (No.1) PERFORMANCE OR STUCK OFF
DTC P0756 SHIFT SOLENOID-B (No.2) PERFORMANCE OR STUCK OFF
CIRCUIT DESCRIPTION
PCM monitors throttle opening, engine speed, vehicle speed and gear position and compares the actual engine
speed and its specified value (i.e., engine speed obtained by PCM through calculation using the throttle open-
ing / gear position and vehicle speed).
DTC DETECTING CONDITION
POSSIBLE CAUSE
While running in “D” range after engine warmed up,
engine speed as compared with vehicle speed is not
within acceptable range.
2 driving cycle detection logic, continuous
monitoring.A / T oil pressure control cable maladjusted
Selector cable maladjusted
Mechanical malfunction of shift solenoid valve
(stick or leakage)
Mechanical malfunction in transmission
Torque converter malfunction
DTC CONFIRMATION PROCEDURE
WARNING:
When performing a road test, select a place where there is no traffic or possibility of a traffic accident
and be very careful during testing to avoid occurrence of an accident.
Road test should be carried out with 2 persons, a driver and a tester, on a level road.
1) Turn ignition switch OFF.
2) Clear DTC with ignition switch ON and warm up engine to normal operating temperature.
3) Shift selector lever to “D” range.
4) Start vehicle and increase vehicle speed to 40 – 55 km / h ( 25 – 35 mile / h) by depressing accelerator pedal half
a stroke.
5) Keep vehicle at above speed for 5 sec. or longer.
6) Increase vehicle speed to 75 – 90 km / h (45 – 55 mile / h) by depressing accelerator pedal half a stroke and keep
it at that speed for 5 sec. or longer.
7) Stop vehicle and check pending DTC and DTC.
7B-30 AUTOMATIC TRANSMISSION (3 A / T) (VEHICLE WITH WU-TWC)
TABLE A-1 NO STARTING OR SLIPPING IN ANY DRIVE RANGE
STEPACTIONYESNO
1Was “AUTOMATIC TRANSMISSION DIAGNOSTIC
FLOW TABLE” performed?Go to Step 2.Go to
“AUTOMATIC
TRANSMISSION
DIAGNOSTIC FLOW
TABLE”.
2Is engine rpm at stall test normal?Transmission
failure.Go to Step 3.
3Is engine rpm at stall test too low in any range?Poor engine power or
torque converter
defective.Go to Step 4.
4Is engine rpm at stall test too high only in “D” range?Go to Step 7.Go to Step 5.
5Is engine rpm at stall test too high only in “R” range?Go to Step 9.Go to Step 6.
6Is line pressure proper?Transmission failure.Oil pump defective,
Regulator valve
operation failure,
Throttle valve
operation failure or
Accelerator cable
and oil pressure
control cable
maladjusted.
7Does engine rpm at stall test become normal when
coupler of solenoid valve wire is disconnected?One-way clutch
operation failure.Go to Step 8.
8Is line pressure proper?Forward clutch worn.Oil leak in forward
clutch oil circuit or Oil
leak in “D” range oil
circuit.
9Does engine rpm at stall test become normal when
coupler of solenoid valve wire is disconnected?1st-Reverse brake
worn.Go to Step 10.
10Is line pressure proper?Direct clutch worn.Oil leak in direct
clutch oil circuit or Oil
leak in “R” range oil
circuit.
AUTOMATIC TRANSMISSION (3 A / T) (VEHICLE WITH WU-TWC) 7B-31
TABLE A-2 GEAR CHANGE FAILURE
STEPACTIONYESNO
1Was “AUTOMATIC TRANSMISSION DIAGNOSTIC
FLOW TABLE” performed?Go to Step 2.Go to “AUTOMATIC
TRANSMISSION
DIAGNOSTIC FLOW
TABLE”.
2Disconnect solenoid valve wire coupler and perform
manual road test.
Is upshift from 1st to 2nd possible?Go to Step 3.1-2 shift valve sticks
or Shift solenoid-B
(2nd brake solenoid)
valve sticks.
3Is upshift from 2nd to 3rd possible?Gear shift control
system defective.
Go to A / T Diagnostic
Flow Table B.2-3 shift valve sticks
or Shift solenoid-A
(Direct clutch
solenoid) valve
sticks.
TABLE A-3 EXCESSIVE SHOCK AT RANGE SELECTION OR GEAR CHANGE
STEPACTIONYESNO
1Was “AUTOMATIC TRANSMISSION DIAGNOSTIC
FLOW TABLE” performed?Go to Step 2.Go to “AUTOMATIC
TRANSMISSION
DIAGNOSTIC FLOW
TABLE”.
2Is line pressure proper?Go to Step 3.Regulator valve
defective, Throttle
valve defective or
Accelerator cable
maladjusted.
3Does excessive shock occur when selecting “D” range
from “N” range?Forward clutch
accumulator
operation failure,
Forward clutch worn
or Forward clutch oil
circuit check ball
operation failure. Go to Step 4.
4Does excessive shock occur when selecting “R” range
from “N” range?1st-Reverse brake
worn, 1st-Reverse
brake oil circuit check
ball operation failure.Go to Step 5.
5Does excessive shock occur at 1st to 2nd gear
change?2nd brake
accumulator
defective, 2nd brake
worn, 2nd brake oil
circuit check ball
operation failure.In case of excessive
shock at 2nd to 3rd
gear change, Direct
clutch worn or Direct
clutch oil circuit check
ball operation failure.
7B-32 AUTOMATIC TRANSMISSION (3 A / T) (VEHICLE WITH WU-TWC)
STALL TEST
This test is to check overall performance of automatic transmission
and engine by measuring stall speed at D and R ranges.
Be sure to perform this test only when transmission fluid is at normal
operating temperature (70–80C / 158–176F) and its level is be-
tween FULL HOT and LOW HOT. (Refer to “Fluid level” in this sec-
tion.)
CAUTION:
Do not run engine at stall more than 5 seconds continuous-
ly, for oil temperature may rise excessively high.
1) Install tachometer.
2) Apply parking brake and block vehicle wheels.
3) Start engine with selector lever shifted to P range.
4) Depress brake pedal.
5) Shift selector lever to D range and depress accelerator pedal ful-
ly while watching tachometer. Read engine rpm quickly when it
has become constant (stall speed).
6) Release accelerator pedal immediately after stall speed is
checked.
7) In the same way, check stall speed at R range.
8) Stall speed should be within following specification.
Stall speed: 2,500 – 2,900 r / min
(For both G10 and G13 engine models)
9) Possible causes for out-of-specification stall speed are as fol-
lows. Check each part which is suspected to be the cause.
Stall speed measured
Possible causes
Lower than specificationEngine output insufficient
Torque converter defective
Higher than specification in
D rangeForward clutch slippage
One-way clutch defective
Higher than specification in
R rangeDirect clutch slippage
1st-reverse brake slippage