Check the fluid level in the gearbox. Fluid must be warm (70-80°C). The engine coolant must also be warmed up (80-90°C).
Block the rear wheels by placing blocks under the wheels.
Connect the engine tachometer.
Apply the parking and service brakes.
Start the engine.
Stopping the gear lever in the position «D», fully depress the accelerator pedal to lock the maximum engine speed. Do not hold the throttle open for more than 5 seconds to obtain maximum engine speed. If more than one lockup test is required, run the engine for about 2 minutes in neutral at 1000 rpm to cool the transmission fluid between tests.
ATTENTION: Critical engine speed when braking the torque converter during the test: 2500±300 rpm.
Set the gear lever to the position «R» and test as described above. If the critical speed is above normal, there is slippage of the rear clutch or freewheel of the transmission (lever position «D»).
If the critical speed is above normal, there is slippage of the front clutch of the gearbox or the brake of the low gear and reverse (lever position «R»). In these cases, test to determine the cause of the slip.
If at lever positions «D» And «R» critical engine speed is below normal, it can be assumed that the engine power is insufficient or the torque converter is malfunctioning. Check for misfiring in the engine, correct ignition timing, valve clearances, etc. If everything is in order in the engine, the torque converter is faulty.