Lexus IS250 IS220d GSE20 ALE20 - A960E AUTOMATIC TRANSMISSION


AUTOMATIC TRANSMISSION SYSTEM - MECHANICAL SYSTEM TESTS

PERFORM MECHANICAL SYSTEM TESTS

Measure the stall speed.


The object of this test is to check the overall performance of the transmission and engine by measuring the stall speeds in the D position.

  • NOTICE:
Driving test should be done on a paved road (a nonskid road).
Perform the test at the normal operating ATF (Automatic Transmission Fluid) temperature 50 to 80°C (122 to 176°F).
Do not continuously run this test for longer than 5 seconds.
To ensure safety, do this test in a wide, clear level area which provides good traction.
The stall 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 doing the test.

Chock the 4 wheels.

Connect an intelligent tester to the DLC3.

Fully apply the parking brake.

Keep your left foot pressed firmly on the brake pedal.

Start the engine.

Shift into the D position. Press all the way down on the accelerator pedal with your right foot.

Quickly read the stall speed at this time.

  • Stall speed:
  • 2,550 +- 150 rpm
Evaluation:
ProblemPossible cause
(a) Stall engine speed is low in D position
Engine power output may be insufficient
Stator one-way clutch not operating properly
  • HINT:
  • If the value is less than the specified value by 600 rpm or more, the torque converter could be faulty.
(b) Stall engine speed is high in D position
Line pressure is too low
Clutch No. 1 (C1) slipping
One-way clutch No. 3 (F3) not operating properly
One-way clutch No .4 (F4) not operating properly
Improper fluid level

Measure the time lag.

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 clutch, and brake.

  • NOTICE:
Perform the test at the normal operating ATF (Automatic Transmission Fluid) temperature: 50 to 80°C (122 to 176°F).
Be sure to allow 1 minute interval between tests.
Perform the test three times, and measure the time lags. Calculate the average value of the three time lags.

Connect an intelligent tester to the DLC3.

Fully apply the parking brake.

Start and warm up the engine and check idle speed.

  • Idle speed:
  • approx. 700 rpm (In N position and A/C OFF)

Shift the lever from N to D position. Using a stop watch, measure the time from when the lever is shifted until the shock is felt.

  • Time lag:
  • N → D less than 1.2 seconds

In the same way, measure the time lag for N → R.

  • Time lag:
  • N → R less than 1.5 seconds
Evaluation (If N → D or N → R time lag is longer than the specified):
ProblemPossible cause
N → D time lag is longer
Line pressure is too low
Clutch No.1 (C1) worn
One-way clutch No. 3 (F3) not operating properly
One-way clutch No. 4 (F4) not operating properly
N → R time lag is longer
Line pressure is too low
Clutch No. 3 (C3) worn
Brake No. 4 (B4) worn
One-way clutch No. 1 (F1) not operating properly
LEXUS IS250, IS220d / GSE20 ALE20
A960E AUTOMATIC TRANSMISSION
Lexus IS250 IS220d GSE20 ALE20
AUTOMATIC TRANSMISSION SYSTEM