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Home >> Lexus >> 2017 >> IS 300 F Sport >> Repair and Diagnosis >> External Pages >> Different car >> Section 29 (Automatic Transmission System (Aa81E, For 8AR-FTS) - Diagnostics - Introduction (1 Of 2)) >> AUTOMATIC TRANSMISSION SYSTEM (for 8AR-FTS) >> Mechanical System Tests [09/2020 - ] >> Mechanical System Tests [09/2020 - ]

Mechanical System Tests [09/2020 - ]

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  1. STALL SPEED TEST 

    HINT: 

    This test is to check the overall performance of the engine and transmission.

    WARNING:
    • This test should be done on a paved surface (a surface that is not slippery).
    • To ensure safety, perform this test in an open and level area that provides good traction.
    • A stall speed test should always be performed with at least 2 people. One person should observe the condition of the wheels and wheel chocks while the other is performing the test.
    NOTE:
    • Do not perform the stall speed test for longer than 5 seconds.
    • When performing the stall speed test repeatedly, wait for 15 seconds or more between tests.
    • Perform this test with the ATF (Automatic Transmission Fluid) at the normal operating temperature: 50 to 80°C (122 to 176°F)
    • Perform this test with the AUTO function (shift-linked function) of the electric parking brake system off.
    1. Connect the Techstream to the DLC3.
    2. Drive the vehicle until the transmission fluid temperature has reached 50 to 80°C (122 to 176°F).
    3. Allow the engine to idle with the air conditioning and headlights off.
    4. Chock all 4 wheels.
    5. Set the parking brake and keep the brake pedal depressed firmly with your left foot.

      HINT: 

      When the parking brake indicator (red) is illuminated after the electric parking brake switch assembly has been pushed to the lock side, the maximum amount of braking force is applied if the electric parking brake switch assembly is pushed to the lock side one more time.

    6. Move the shift lever to D.
    7. Depress the accelerator pedal as much as possible with your right foot.
    8. Read the engine speed (stall speed) and release the accelerator pedal immediately.

      Standard Value

      Stall Speed
      2840 rpm + 150 rpm
      - 150 rpm
      EVALUATION

      Test Result Possible Cause
      Stall speed is lower than standard value
      • 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 may be faulty.
      Stall speed is higher than standard value
      • Line pressure is too low
      • Forward multiple clutch (C1) slipping
      • No. 1 one-way clutch (F1) is not operating properly
      • Improper fluid level
  2. SHIFT TIME LAG TEST 
    NOTE:

    Perform this test with the AUTO function (shift-linked function) of the electric parking brake system off.

    HINT: 

    When the shift lever is moved while the engine is idling, there will be a certain time lapse or lag before shock can be felt. This is used for checking the condition of the clutch and brake.

    1. Connect the Techstream to the DLC3.
    2. Drive the vehicle until the transmission fluid temperature has reached 50 to 80°C (122 to 176°F).
    3. Allow the engine to idle with the air conditioning off.
    4. Set the parking brake and keep the brake pedal depressed firmly.

      HINT: 

      When the parking brake indicator (red) is illuminated after the electric parking brake switch assembly has been pushed to the lock side, the maximum amount of braking force is applied if the electric parking brake switch assembly is pushed to the lock side one more time.

    5. Check the D position time lag.
      1. Move the shift lever to N and wait for 1 minute.
      2. Move the shift lever to D and measure the time until shock is felt.
      3. Repeat the 2 steps above 3 times, and calculate the average time of the 3 tests.

        Standard Value

        D position time lag is less than 0.8 seconds

    6. Check the R position time lag.
      1. Move the shift lever to N and wait for 1 minute.
      2. Move the shift lever to R and measure the time until shock is felt.
      3. Repeat the 2 steps above 3 times, and calculate the average time of the 3 tests.

        Standard Value

        R position time lag is less than 1.2 seconds

        EVALUATION

        Test Result Possible Cause
        D position time lag exceeds standard value
        • Line pressure is low
        • Forward multiple clutch (C1) is worn
        • No. 1 one-way clutch (F1) is not operating properly
        R position time lag exceeds standard value
        • Line pressure is low
        • Reverse clutch (C4) is worn
        • No. 2 brake (B2) is worn