The test consists of determining the maximum engine speed with the throttle fully open and the shift lever positions "D" and "R". This test checks the operation of the torque converter stator overrunning clutch and the clutches of the gearbox and the low and reverse brake.
Warning. During this test, make sure that no one is in front of or behind the vehicle.
1. Check the transmission fluid level. The fluid should be at normal operating temperature (80-90°C). The engine coolant should also be at normal operating temperature (80-90°C).
2. Place chocks under both rear wheels.
3. Connect the tachometer to the engine.
4. Apply the parking and service brakes.
5. Start the engine.
6. With the gearshift lever in position "D", fully depress the accelerator pedal to maintain maximum engine speed. Do not hold the throttle open longer than necessary to obtain maximum engine speed, and never longer than 5 seconds at a time. If more than one parked test is required, run the engine in neutral at approximately 1000 rpm for approximately 2 minutes to cool the transmission fluid between tests.
The critical rotation speed during testing is 2300-2700 rpm.
7. Set the gearshift lever to the "R" position and carry out the test using the above described method.
If the critical frequency, with the lever position "D", is higher than normal, there is slippage of the rear clutch or overrunning clutch of the gearbox. In this case, perform hydraulic tests to determine the cause of slippage.
If the critical speed with the "R" lever position is higher than normal, there is slippage of the front clutch of the gearbox or the low gear and reverse brake. In this case, perform hydraulic tests to determine the cause of slippage.
If the critical speed at the "D" to "R" lever positions is below the norm, it can be assumed that the engine power is insufficient or the torque converter is faulty. Check for misfires in the engine, correct ignition timing, clearances, valves, etc. d. If everything is OK with the engine, the torque converter is faulty.