engine LEXUS SC400 1991 Service Workshop Manual

(c) Check for abnormal noise and vibration.Run at the D position lock±up or O/D gear and check for ab-
normal noise and vibration.
HINT: The check for the cause of abnormal noise and vibra-
tion must be performed very thoroughly care as it could also
be due to loss of balance in the propeller shaft, differential,
torque converter clutch, etc..
(d) Check kick±down operation While running in the D position, 2nd, 3rd and O/D gears,
check to see that the possible kick±down vehicle speed limits
for 2 "1, 3 "2 and O/D "3 kick±downs conform to those indi-
cated on the automatic shift schedule. (See page AT±45)
(e) Check abnormal shock and slip at kick±down.
(f) Check the lock±up mechanism. (1) Drive in D position, O/D gear, at a steady speed (lock±upON) of about 58 km/h (36 mph).
(2) Lightly depress the accelerator pedal and check that the engine RPM does not change abruptly.
If there is a big jump in engine RPM, there is no lock±up.
2. 2 POSITION TEST Shift into the 2 position and fully depress the accelerator ped-
al and check the following points:
(a) Check up±shift operation Check to see that the 1 "2 up±shift takes place and that the
shift point conforms to that shown on the automatic shift
schedule. (See page AT±45)
HINT:
w There is no O/D up±shift and lock±up in the 2 position.
(b) Check engine braking While running in the 2 position and 2nd gear, release the ac-
celerator pedal and check the engine braking effect.
AT±42
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(c) Check for abnormal noise during acceleration anddeceleration, and for shock at up±shift and down±shift.
3. L POSITION TEST Shift into the 2 position and fully depress the accelerator ped-
al and check the following points:
(a) Check no up±shift While running in the L position, check to see that there is no
up±shift to 2nd gear.
(b) Check engine braking While running in the L position, release the accelerator pedal
and check the engine braking effect.
(c) C h e c k f o r a bnormal noise during acceleration and
deceleration.
4. R POSITION TEST Shift into the R position and fully depress the accelerator ped-
al and check for slipping.
CAUTION: Before conducting this test ensure that the test area
is free from personnel and obstructor.
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PWR Mode (Kick±down foot switch deactivated)
Shift positionShifting pointVehicle speed km/h (mph)  Throttle valve fully opened 1"2 67±71 (42±44)  2"3 118±124 (73±77)  3"O/D 179±186 (111±116) 
Dposition
 O/D"3 149±155 (93±96) D position 3"2 95±100 (59±62)  2"1 22±26 (14±16)  Throttle valve fully closed 3"O/D 32±35 (20±22)  O/D"3 23±26 (14±16)  Throttle valve fully opened 1"2 67±71 (42±44) 
2 position
 3"2 106±112 (66±70)  2"1 10±13 (6±8) 
Lposition
 Throttle valve fully opened 3"2 104±109 (65±68) L position 2"1 57±63 (35±39)
LOCK±UP POINT
NORM Mode
 D position km/h (mph) 
Lock±upON
 
Lock±upOFF Throttle valve opening 5% Lock±up ON Lock±up OFF
 *3rd Gear 83±88 (52±55) 77±82 (48±51)
 O/D Gear 56±60 (35±37) 53±57 (33±35)
*: O/D Switch OFF
PWR Mode
D position km/h (mph)Lock±upONLock±upOFF Throttle valve opening 5%Lock±up ONLock±up OFF
 *3rd Gear 83±88 (52±55) 77±82 (48±51)
 O/D Gear 56±60 (35±37) 53±57 (33±35)
*: O/D Switch OFF
HINT:
(1) There is no lock±up in the 2 and L positions.
(2) In the following cases, the lock±up will be released regardless\
of the lock±up pattern.

When the throttle valve is completely closed.

When the brake light switch is ON.
(3) Shift up to 3rd will not occur when the engine coolant temp. is below 3\
5 C (95 F) and the vehicle speed
is below 40 km/h (25 mph).
(4) Shift±up to O/D will not occur when the engine coolant temp. is\
below 60 C (140 F) and the vehicle
speed is below 63 km/h (39 mph).
(5) During cruise control operation, the shift pattern is fixed in NOR\
M. And when the vehicle speed drops to 10 km/h (6 mph) or more below the cruise control set vehicle speed, s\
hift down from O/D to 3rd
occurs.
(6) The kick±down foot switch turns ON when the accelerator pedal i\
s depressed further with the throttle valve already fully open.
AT±46
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AT00S±01
PRELIMINARY CHECK
1. CHECK FLUID LEVELHINT:
wDrive the vehicle so that the engine and transmission
are at normal operating temperature.
Fluid temp.: 70±80 5C (158±176 5F)
w Only use the COOL range on the dipstick as a rough
reference when the fluid is replaced or the engine does
not run.
(a) Park the vehicle on a level surface and set the parking brake.
(b) With the engine idling and the brake pedal depressed, shift the shift lever into all positions from P to L position and return
to P position.
(c) Pull out the transmission dipstick and wipe it clean.
(d) Push it back fully into the tube.
(e) Pull it out and check that the fluid level is in the HOT range. If the level is at the low side, add fluid.
Fluid type:
ATF TYPE T±II or Equivalent
NOTICE: Do not overfill.
2. CHECK FLUID CONDITION If the fluid smells burnt or is black, replace it.
3. REPLACE TRANSMISSION FLUID
(a) Remove the drain plug and drain the fluid.
(b) Reinstall the drain plug securely.
(c) With the engine OFF, add new fluid through the oil filler tube.
Fluid type:
ATF TYPE T±II or Equivalent
Capacity:
Total: 8.2 liters (8.7 US qts, 7.2 lmp. qts)
Drain and refill: 1.9 liters (2.0 US qts, 1.7 lmp. qts)
(d) Start the engine and shift the shift lever into all positions fromP to L position and then shift into P position.
(e) With the engine idling, check the fluid level. Add fluid up to the
COOL level on the dipstick.
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(f) Check the fluid level at the normal operating temperature70±80
C (158±176
F) and add as necessary.
NOTICE: Do not overfill.
4. CHECK FLUID LEAKS
Check for leaks in the transmission.
If there are leaks, it is necessary to repair or replace O±rings,
seal packings, oil seals, plugs or other parts.
5. INSPECT AND ADJUST THROTTLE CABLE
(a) Remove the 2 bolts, nut and throttle body cover.
(b) Check that the throttle valve is fully closed.
(c) Check that the inner cable is not slack.
(d) Measure the distance between the outer cable end and stopper on the cable.
Standard distance:
0±1 mm (0±0.04 in.)
If the distance is not standard, adjust the cable by the adjust-
ing nuts.
(e) Install the throttle body cover, and two bolts and nut.
6. INSPECT AND ADJUST SHIFT LEVER POSITION When shifting the shift lever from the N position to other posi-
tions, check that the lever can be shifted smoothly and accu-
rately to each position and that the position indicator correctly
indicates the position.
If the indicator is not aligned with the correct position, carry
out the following adjustment procedures:
(a) Loosen the nut on the control shaft lever.
(b) Push the control shaft lever fully rearward.
(c) Return the control shaft lever 2 notches to N position.
(d) Set the shift lever to N position.
(e) While holding the shift lever lightly toward the R position side,
tighten the shift lever nut.
(f) Start the engine and make sure that the vehicle moves forward when shifting the lever from the N to D position and
reverses when shifting it to the R position.
AT±48
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7. INSPECT AND ADJUST PARK/NEUTRAL POSITION
SWITCH
Check that the engine can be started with the shift lever only
in the N or P position, but not in other positions.
If not as started above, carry out the following adjustment
procedure:
(a) Loosen the park/neutral position switch bolt and set the shift lever to the N position.
(b) Align the groove and neutral basic line.
(c) Hold in position and tighten the bolt.
Torque: 12 N Vm (125 kgf Vcm, 9 ft Vlbf)
For continuity inspection of the park/neutral position switch,
see page AT±106.
8. INSPECT IDLE SPEED
Idle speed:
650 RPM (In N position and air conditioner OFF)
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MECHANICAL SYSTEM TESTS
AT0QT±01
STALL TESTThe object of this test is to check the overall performance of the trans\
mission and engine by measuring
the stall speeds in the D and R positions.
NOTICE:
 Perform the test at normal operating fluid temperature 50±80 C (122±176 F).
 Do not continuously run this test longer than 5 seconds.
 To ensure safety, conduct this test in a wide, clear, level area, which provides good traction.
 The stall test should always be carried out in pairs. One technician sho\
uld observe the conditions of
wheels or wheel stoppers outside the vehicle while the other is performi\
ng the test.
MEASURE STALL SPEED
(a) Chock the 4 wheels.
(b) Connect a tachometer to the engine.
(c) Fully apply the parking brake.
(d) Keep your left foot pressed firmly on the brake pedal.
(e) Start the engine.
(f) Shift into the D position. Step all the way down on the accelerator peda\
l 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 position.
AT±50±
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EVALUATION
 

Problem\
 
\

\
Possible cause 


\
 
\

\

Engine output may be insufficient.
 \
 \
 Stator one±way clutch is operating properly
 (a) Stall speed low in D and R positions.\
 \
HINT:
 \
 \
If more than 600 RPM below the specified value, the
 \
 \
torque converter could be faulty.
 \
 \
 Line pressure too low
 
(b) Stall speed high in Dposition
\
 \
 Forward clutch slopping 

(b) Stall speed high in D position.\
 
\
 No.2 one±way clutch not operating properly 


\
 
\

\

O/D one±way clutch not operating properly
 \
 \
 Line pressure too low
 (c) Stall speed high in Rposition\
 \
 Direct clutch slipping
 (c) Stall speed high in R position.\
 \
 First and reverse brake slipping
 \
 \
 O/D one±way clutch not operating properly
 \
 \
 Line pressure too low
 (d) Stall speed high in D and R position.\
 \
 Improper fluid level 

\
 
\
 O/D one±way clutch not operating properly
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TIME LAG TEST
When the shift lever is shifted while the engine is idling, there will be a \
certain time lapse or lag before the
shock can be felt. This is used for checking the condition of the O/D direct \
clutch, forward clutch, direct
clutch, and first and reverse brake.
NOTICE:
Perform the test at normal operating fluid temperature 50±80 C (122±176 F).
 Be sure to allow a one minute interval between tests.
 Make 3 measurements and take the average value.
MEASURE TIME LAG
(a) Fully apply the parking brake
(b) Start the engine and check idle speed.
Idle speed:
650 RPM (In N position and air conditioner OFF)
(c) Shift the shift lever from N to D position. Using a stop watch, measure the time it take\
s from shifting thelever until the shock is felt.
In same manner, measure the time lag for N
R.
Time lag:
N D Less than 1.2 seconds
N R Less than 1.5 seconds
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MEASURE LINE PRESSURE
NOTICE:
Perform the test at normal operating fluid temperature 50±80 C (122±176 F).
 The line pressure test should always be carried out in pairs. One technicia\
n should observe the
conditions of wheels or wheel stoppers outside the vehicle while the other is perf\
orming the test.
 Be careful to prevent the oil pressure gauge hose from interfering with \
the exhaust pipe.
(a) Warm up the transmission fluid.
(b) Remove the test plug on the transmission case left side and connect the \
oil pressure gauge SST.
SST 09992±00094
HINT: Connecting the oil pressure gauge will be made easier by moving LH sid\
e heat insulator aside.
(c) Fully apply the parking brake and chock the 4 wheels.
(d) Start the engine and check idling RPM.
(e) Keep your left foot pressed firmly on the brake pedal and shift into D p\
osition.
(f) Measure the line pressure when the engine is idling.
(g) Press the accelerator pedal all the way down. Quickly read the highest line pressure when engine speedreaches stall speed.
(h) In the same manner, perform the test in R position. AT±54
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