AUTOMATIC TRANSMISSION SYSTEM MECHANICAL SYSTEM TESTS


  1. PERFORM MECHANICAL SYSTEM TESTS


    1. 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.

      Note


      • Driving test should be done on a paved road (a nonskid road).

      • Perform the test at the normal operating ATF (Automatic Transmission Fluid) temperature 60 to 90°C (140 to 194°F).

      • Do not continuously run this test for longer than 5 seconds.

      • After performing the stall test, move the shift lever to P or N. And then, with the engine speed of no more than 1200 rpm, cool down the transmission for at least 1 minute.

      • If the engine speed in the stall test exceeds the specified value, immediately stop the test to prevent the transmission from getting damaged.

      • 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.

      • Be sure to perform the test after inspecting and adjusting the engine.


      1. Check the 4 wheels.

      2. Connect the GTS to the DLC3.

      3. Fully apply the parking brake.

      4. Keep your left foot pressed firmly on the brake pedal.

      5. Start the engine.

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

      7. Quickly read the stall speed at this time.

        Evaluation:
        Problem Possible cause
        (a) Stall engine speed is low in D position

        • Engine power output may be insufficient

        • Stator one-way clutch not operating properly

        Tech Tips

        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.


    1. 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.

      Note


      • Be sure to perform a road test after inspecting and adjusting the engine.

      • Fully apply the parking brake and chock the 4 wheels.

      • Perform the test at the normal operating ATF (Automatic Transmission Fluid) temperature: 60 to 90°C (140 to 194°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.

      • Perform these tests with the air conditioning off.

      • Be sure to perform the test after inspecting and adjusting the engine.

    2. Connect the GTS to the DLC3.

    3. Fully apply the parking brake.

    4. Start and warm up the engine and check idle speed.

    5. While depressing the brake pedal, move the shift lever from N to D. Using a stop watch, measure the time from when the lever is shifted until the shock is felt.

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

      7. Evaluation (If N → D or N → R time lag is longer than the specified):
      Problem Possible 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