Warning: Make sure no one is in front of or behind the vehicle during this test.
1. Check the fluid level in the gearbox. The fluid should be at normal operating temperature (70-80°C).
Engine coolant should also be at normal operating temperature (80-90°C).
2. Place chocks under the rear wheels.
3. Connect the engine tachometer.
4. Apply the parking and service brakes.
5. Start the engine.
6. With the gearshift lever in the "D" position, fully depress the accelerator pedal to lock in 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 lock-up test is required, run the engine in neutral at about 1000 rpm for about 2 minutes to cool the transmission fluid between tests.
- Critical engine speed during torque converter braking during testing: 2500±3000 rpm
7. Set the gear shift lever to the "R" position and carry out the test using the above described method.
If the critical speed is higher than normal, there is slippage of the rear clutch or overrunning clutch of the gearbox (lever position "O").
If the critical speed is higher than normal, there is slippage of the front clutch of the transmission or the low and reverse brake (lever position "R"). In these cases, conduct tests to determine the cause of slippage.
If the critical rotation speed is below the norm with the lever in the "O" and "R" positions, it is possible to assume that the engine power is insufficient or the torque converter is faulty. Check for misfires in the engine, correct ignition timing, valve clearances, etc. If everything is in order in the engine, the torque converter is faulty.