Lexus SC300 / Lexus SC400. Manual - part 74

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)

lever until the shock is felt.
In same manner, measure the time lag for N

Time lag:

N D Less than 1.2 seconds

N R Less than 1.5 seconds

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A304E (1UZ–FE) AUTOMATIC TRANSMISSION

TROUBLESHOOTING

EVALUATION

If N

→

D or N

→

R time lag are longer than specified:

ÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑ

Problem

ÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑ

Possible cause

ÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑ

→

D time lag is longer

ÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑ

Line pressure too low

Forward clutch worn

O/D one–way clutch not operating properly

Accumulator back pressure too low

ÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑ

→

R time lag is longer

ÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑ

Line pressure too low

Direct clutch worn

First and reverse brake worn

O/D one–way clutch not operating properly

Accumulator back pressure too low

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A304E (1UZ–FE) AUTOMATIC TRANSMISSION

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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 technician should observe the

conditions of wheels or wheel stoppers outside the vehicle while the other is performing 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 side 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 position.
(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 speed

reaches stall speed.

(h) In the same manner, perform the test in R position.

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A304E (1UZ–FE) AUTOMATIC TRANSMISSION

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SPECIFIED LINE PRESSURE

ÑÑÑÑÑÑÑÑÑÑÑ

Condition

ÑÑÑÑÑÑÑÑÑÑÑÑÑ

D positionkPa

(kgf/cm

, psi)

ÑÑÑÑÑÑÑÑÑÑÑÑÑÑ

R positionkPa

(kgf/cm

, psi)

ÑÑÑÑÑÑÑÑÑÑÑ

Idling

ÑÑÑÑÑÑÑÑÑÑÑÑÑ

382–441 (3.9–4.5, 55–64)

ÑÑÑÑÑÑÑÑÑÑÑÑÑÑ

637–716 (6.5–7.3, 92–104)

ÑÑÑÑÑÑÑÑÑÑÑ

Stall

ÑÑÑÑÑÑÑÑÑÑÑÑÑ

1,265–1,402 (12.9–14.3, 183–203)

ÑÑÑÑÑÑÑÑÑÑÑÑÑÑ

1,726–2,060 (17.6–21.0, 250–299)

If the measured pressures are not up to specified values, recheck the throttle cable adjustment and perform
a retest.

EVALUATION

ÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑ

Problem

ÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑ

Possible cause

ÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑ

ÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑ

Throttle cable out of adjustment

ÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑ

If the measured values at all positions are higher.

ÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑ

Throttle valve defective

ÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑ

ÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑ

Regulator valve defective

ÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑ

ÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑ

Throttle cable out of adjustment

ÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑ

ÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑ

Throttle valve defective

ÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑ

If the measured values at all positions are lower.

ÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑ

Regulator valve defective

ÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑ

ÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑ

Oil pump defective

ÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑ

ÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑ

O/D direct clutch defective

ÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑ

If pressure is low in the D position only

ÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑ

D position circuit fluid leakage

ÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑ

If pressure is low in the D position only.

ÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑ

Forward clutch defective

ÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑ

ÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑ

R position circuit fluid leakage

ÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑ

If pressure is low in the R position only.

ÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑ

Direct clutch defective

ÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑ

ÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑÑ

First and reverse brake defective

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A304E (1UZ–FE) AUTOMATIC TRANSMISSION

TROUBLESHOOTING

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