ABBREVIATIONS USED IN THIS MANUAL
A/T ATM Automatic Transmission
ATF Automatic Transmission Fluid
B
0 Overdrive Brake
B
1 Second Coast Brake
B
2 Second Brake
B
3 First and Reverse Brake
C
0 Overdrive Clutch
C
1 Forward Clutch
C
2 Direct Clutch
D Disc
D/F Differential
LH Left
MP Multipurpose
O/D Overdrive
P Plate
RH Right
SSM Special Service Materials
SST Special Service Tools
IN-6- INTRODUCTIONAbbreviations Used in This Manual
VALVE BODY
Hydraulic Control System
A540E, A540H
The hydraulic control system is composed of the oil pump, the valve body, the solenoid valves, the accu-
mulators, the clutches and brakes, and the governor valve 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 hy-
draulic 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.
The No. 1 and No. 2 solenoid valves are turned on and off by signals from ECU to operate the shift valves
and change the gear shift position.
The No. 3 solenoid valve is operated by signals from the ECU to engage or disengage the lock-up clutch
of the torque converter.
A540H
There are two center differential control solenoid valves on the transfer.
The solenoid valves are adjusting the center differential control pressure.
HYDRAULIC CONTROL SYSTEM
Hydr. pressure control
OIL PUMP
CLUTCHES & BRAKESFluid passage switchingPlanetary gear unit
Torque converter
Throttle Cable
SOLENOID VALVES
ECU
AT-8- AUTOMATIC TRANSAXLEOperation
COMPONENT PARTS
General Notes
The instructions here are organized so that you work on only one component group at a time.
This will help avoid confusion from similar-looking parts of different subassemblies being on
your workbench at the same time.
The component groups are inspected and repaired from the converter housing side.
As much as possible, complete the inspection, repair and assembly before proceeding to the
next component group. If a component group can not be assembled because parts are being or-
dered, be sure to keep all parts of that group in a separate container while proceeding with disas-
sembly, inspection, repair and assembly of other component groups.
Recommended fluid for the automatic transaxle: A540E ATF DEXRON II
A540H ATF Type T or equivalent
Recommended oil for the transfer: Transaxle oil E50, API GL5, SAE 75W-90 or equivalent
GENERAL CLEANING NOTES:
1. All disassembled parts should be washed clean, with any fluid passages and holes blown
through with compressed air.
2. When using compressed air to dry parts, always aim away from yourself to prevent acciden-
tally spraying automatic transaxle fluid or kerosene in your face.
3. The recommended automatic transaxle fluid or kerosene should be used for cleaning.
PARTS ARRANGEMENT:
1. After cleaning, the parts should be arranged in proper order to allow efficient inspection,
repairs, and reassembly.
2. When disassembling a valve body, be sure to keep each valve together with the corre-
sponding spring.
3. New brakes and clutches that are to be used for replacement must be soaked in transaxle
fluid for at least fifteen minutes before assembly.
GENERAL ASSEMBLY:
1. All oil seal rings, clutch discs, clutch plates, rotating parts, and sliding surfaces should be
coated with transmission fluid prior to reassembly.
2. All gaskets and rubber O-rings should be replaced.
3. Make sure that the ends of a snap ring are not aligned with one of the cutouts and are
installed in the groove correctly.
4. If a worn bushing is to be replaced, the subassembly containing that bushing must be re-
placed.
5. Check thrust bearings and races for wear or damage. Replace if necessary.
6. Use petroleum jelly to keep parts in place.
- AUTOMATIC TRANSAXLEComponent Parts (General Notes)AT-39
3. Hydraulic Control System
CONSTRUCTION
The hydraulic control is composed of an oil pump, rotated by the engine, which supplies hydraulic pres-
sure; a valve body which controls the hydraulic pressure and the opening and closing of the fluid pas-
saged; and a governor valve which supplies hydraulic pressure in accordance with vehicle speed.
OPERATION
Hydraulic pressure supplied by the oil pump is controlled± by the regulator valve; the resulting oil pres-
sure controlled by the regulator valve is called the line pressure.
Line pressure produces the hydraulic pressure for throttle pressure and governor pressure. Also, line
pressure produces hydraulic pressure for the operation of each brake and clutch in the planetary gear
unit.
The throttle valve acts to produce hydraulic pressure, called the throttle pressure, which responds to ac-
celerator pedal modulation. Throttle pressure increases as the accelerator pedal is depressed.
The governor valve produces hydraulic pressure, called the governor pressure, in response to vehicle
speed. Governor pressure increases as vehicle speed increases.
In accordance with the difference between throttle pressure and governor pressure, each shift valve
shifts, the fluid passages to the clutches are brakes in the planetary gear unit are opened and the
clutches and brakes operate, and shift change occurs.
The operation of the hydraulic control system, using the 2±3 shift valve as an example, is shown below;
± AUTOMATIC TRANSAXLEDescription (A140L and A140E)AT±8
Preliminary Check
11. CHECK FLUID LEVEL
HINT: The vehicle must have been driven so that the
engine and transmission are at normal operating tem-
perature. (fluid temperature: 158 ± 176
°F or 70 ±80°C)
(a) Park the vehicle on a level surface, set the parking
brake.
(b) With the engine idling, shift the shift lever into all posi-
tions from P to L position and return to P position.
HINT: Depress the brake pedal.
(a) Pull out the transaxle dipstick and wipe it clean.
(b) Push it back fully into the tube.
(c) Pull it out and check that the fluid level is in the HOT
range. If the level is at the low side of the hot range,
add fluid.
Fluid type: ATF DEXRON) II
NOTICE: Do not overfill.
2. CHECK FLUID CONDITION
If the fluid smells burnt or is black, replace it
3. REPLACE ATF
NOTICE: Do not overfill.
(a) Remove the drain plug and drain the fluid.
(b) Reinstall the drain plug securely.
(c) With the engine OFF, and new fluid through the dip
stick tube.
SST 09043±38100
Fluid: ATF DEXRON) II
Capacity:
Dry fill:
A140E 5.3 liters (5.6 US qts, 4.7 Imp. qts)
A140L 5.7 liters (6.0 U S qts, 5.0 Imp. qts)
Drain and refill (Reference):
140E, A140L 2.5 liters (2.6 US qts, 2.2 Imp. qts)
(d) Start the engine and shift the selector into all positions
from P through L and then shift into P.
(e) With the engine idling, check the fluid level. Add fluid
up to the ºCOOLº level on the dipstick.
(f) Check the fluid level with the normal fluid temperature
(158 ± 176
°F or 70 ± 80°C) and add as necessary.
NOTICE: Do not overfill.
± AUTOMATIC TRANSAXLETroubleshooting (Preliminary Check) (A140L and A140E)AT±21
Mechanical System Tests
STALL TEST
The object of this test is to check the overall performance of the transaxle and engine by measur-
ing the stall speeds in the D and R ranges.
CAUTION:
wPerform the test at normal operation fluid temperature (122 ± 176°F or 50 ± 80°C).
wDo not continuously run this test longer than 5 seconds.
wTo ensure safety, conduct this test in a wide, clear, level area, which provides good traction.
wThe stall test should always be carried out in pairs. One should observe the conditions of wheels
or wheel stoppers outside the vehicle while the other is performing the test.
MEASURE STALL SPEED
(a) Chock the front and rear wheels.
(b) Connect a tachometer to the engine.
(c) Fully apply the parking brake.
(d) Step down strongly on the brake pedal with your left foot.
(e) Start the engine.
(f) Shift into the D range. Step all the way down on the accelerator pedal with your right foot. Quickly
read the stall speed at this time.
Stall speed: 2,200
+150 rpm
(g) Perform the same test in R range.
EVALUATION
(a) If the stall speed is the same for both ranges without the rear wheels rotating but lower than specified
value:
wEngine output may be insufficient
w Stator one±way clutch is not operating properly
(b) If the stall speed in D range is higher than specified:
wLine pressure too low
wForward clutch slipping
wNo. 2 one±way clutch not operating properly
wO/D one±way clutch not operating properly
(c) If the stall speed in R range is higher than specified:
wLine pressure too low
wDirect clutch slipping
wFirst and reverse brake slipping
wO/D one±way clutch not operating properly
(d) If the stall speed in both R and D ranges are higher than specified:
wLine pressure too low
wImproper fluid level
wO/D one±way clutch not operating properly
± AUTOMATIC TRANSAXLETroubleshooting (Mechanical System Tests) (A140L and
A140E)AT±38
TIME LAG TEST
When the shift lever is shifted while the engine is idling, there will be a certain time elapse or lag
before the shock can be felt. This is used for checking the condition of the O/D direct clutch, for-
ward clutch, direct clutch and first and reverse brake.
NOTICE:
wPerform the test at normal operating fluid temperature (122 ±176°F or 50 ± 80°C).
wBe sure to allow one minute interval between tests.
wMake three measurements and take the average value.
MEASURE TIME LAG
(a) Fully apply the parking brake.
(b) Start the engine and check the idle speed.
Idle speed (N range) : 700 rpm
(c) Shift the shift lever from N to D position. Using a stop watch, measure the time it takes from shifting
the lever until the shock is felt.
Time lag: Less than 1.2 seconds
(d) In the same manner, measure the time lag for N ± R.
Time lag: Less than 1.5 seconds
EVALUATION
(a) If N ± D time lag is longer than specified:
wLine pressure too low
wForward clutch worn
wO/D one±way clutch not operating properly
(b) If N ± R time lag is longer than specified:
wLine pressure too low
wDirect clutch worn
wFirst and reverse brake worn
wO/D one±way clutch not operating properly
± AUTOMATIC TRANSAXLETroubleshooting (Mechanical System Tests) (A140L and
A140E)AT±39
HYDRAULIC TEST
PREPARATION
(a) Warm up the transaxle fluid.
(b) Remove the transaxle case test plug and connect the hydraulic pressure gauge.
SST 09992±00094 (Oil pressure gauge)
NOTICE:
wPerform the test at normal operating fluid temperature (122 ±176°F or 50 ± 80°C).
wThe line pressure test should always be carried out in pairs. One should observe the conditions
of wheels or wheel stoppers outside the vehicle while the other is performing the test.
MEASURE LINE PRESSURE
(a) Fully apply the parking brake and chock the four wheels.
(b) Start the engine and check idling rpm.
(e) Step down strongly on the brake pedal with your left foot and shift into D range.
(d) Measure the line pressure when the engine is idling.
(e) Press the accelerator pedal all the way down. Quickly read the highest line pressure when engine
speed reaches stall speed.
(f) In the same manner, perform the test in R range.
If the measured pressure are not up to specified values, recheck the throttle cable adjustment and
perform a retest.
kg/cm (psi, kPa)
Line pressure
R range D range
Idling
IdlingStall
Stall
± AUTOMATIC TRANSAXLETroubleshooting (Mechanical System Tests) (A140L and
A140E)AT±40