automatic transmission fluid LEXUS SC300 1991 Service Repair Manual

ABBREVIATIONS USED IN THIS
MANUAL
ABS Anti±Lock Brake System J/B Junction Block
A/C Air Conditioner LED Light Emitting Diode
ALR Automatic Locking Retractor LH Left±Hand
APPROX. Approximation LHD Left±Hand Drive
A/T, ATM Automatic Transmission LLC Long Life Coolant (Year Around Coolant)
ATF Automatic Transmission Fluid Max. Maximum
BTDC Before Top Dead Center Min. Minimum
BVSV Bimetal Vacuum Switching Valve MP Multipurpose
CALIF. Vehicles Sold in California N Neutral
CB Circuit Breaker OD, O/D Overdrive
DOHC Double Over Head Cam O/S Oversize
DP Dash Pot P & BV Proportioning and Bypass Valve
ECT Electronic Controlled Transmission PCV Positive Crankcase Ventilation
ECU Electronic Controlled Unit PS Power Steering
EFI Electronic Fuel Injection RH Right±Hand
EGR Exhaust Gas Recirculation RL Rear Left
ELR Emergency Locking Retractor RR Rear Right
EPR Evaporator Pressure Regulator RR, Rr Rear
ESA Electronic Spark Advance SRS Supplemental Restraint System
EVAP Evaporative (Emission Control) SSM Special Service Materials
EX Exhaust (manifold, valve) SST Special Service Tools
Ex. Except STD Standard
FIPG Formed in Place Gasket SW Switch
FL Front Left TDC Top Dead Center
FL Fusible Link TDCL Total Diagnostic Communication Link
FPU Fuel Pressure Up Temp. Temperature
FR Front Right TRAC Traction Control System
FR, Fr Front TWC Three±Way Catalyst
HAC High Altitude Compensation VSV Vacuum Switching Valve
IG Ignition VTV Vacuum Transmitting Valve
IN Intake (manifold, valve) w/ With
INT Intermittent w/o Without
ISC Idle Speed Control
IN±34±
INTRODUCTION Abbreviations Used in This Manual
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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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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
AT±52±
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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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SPECIFIED LINE PRESSURE
 
Condition
 
D positionkPa (kgf/cm2, psi)
 
R positionkPa (kgf/cm2, psi) 

Idling
 

382±441 (3.9±4.5, 55±64)
 

637±716 (6.5±7.3, 92±104) 

Stall
 

1,265±1,402 (12.9±14.3, 183±203)
 

1,726±2,060 (17.6±21.0, 250±299)
If the measured pressures are not up to specified values, recheck the thro\
ttle cable adjustment and perform
a retest.
EVALUATION
 Problem\
 \
Possible cause
 \
 \

Throttle cable out of adjustment If the measured values at all positions are higher.\
 \
 Throttle valve defective 


\

\

\

Regulator valve defective
 \
 \
 Throttle cable out of adjustment
 \
 \
 Throttle valve defective
 If the measured values at all positions are lower.\
 \
 Regulator valve defective
 \
 \
 Oil pump defective
 \
 \
 O/D direct clutch defective
 
Ifpressure is low in the Dposition only
\
 \
 D position circuit fluid leakage If pressure is low in the D position only.\
 \
 Forward clutch defective 


\

\

\

R position circuit fluid leakage
 If pressure is low in the R position only.\
 \
 Direct clutch defective
 \
 \
 First and reverse brake defective
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MEASURE ACCUMULATOR BACK PRESSURE
AT0QU±01
NOTICE:
Perform the test at normal operating fluid temperature 50±80 C (122±176 F).
 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 rear right side and connec\
t the oil pressure gauge SST.
SST 09992±00094
HINT: Connecting the oil pressure gauge will be made easier by moving the RH \
side head insulator aside.
(c) Remove the passenger side No.2 under cover and ECM protector.
(d) Connect the SST (check harness A) between ECM and connector of vehicle\
wire harness.
SST: 09990±01000
(e) Install one test lead probe into the terminal SLN of the ECM wire harnes\
s side connector and take care not to ground the other test lead probe.
HINT: Prepare test leads which are connected with an (approximately) 8 W l\
ight bulb.
AT±56
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2. HYDRAULIC CONTROL SYSTEMThe hydraulic control system is composed of the oil pump, the valve body, the solenoid valves, the accumu-
lators, the clutches and brakes, as well as the fluid passages which connect al\
l of these components.
Based on the hydraulic pressure created by the oil pump, the hydraulic control system governs the hydrau-
lic pressure acting on the torque converter clutch, clutches and brakes \
in accordance with the vehicle driv-
ing conditions.
There are 4 solenoid valves on the valve body.
The No.1 and No.2 solenoid valves are turned on and off by signals from the ECM to operate the shift
valves, and change the gear shift position.
The No.3 solenoid valve is operated by signals from the ECM to engage or di\
sengage the lock±up clutch
of the torque converter clutch.
The No.4 solenoid valve is operated by signals from the ECM to control the \
engagement speed and reduce
gear shift shock.
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A304E (1UZ±FE) AUTOMATIC TRANSMISSION OPERATIONAT±7
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