Checking the torque converter on a fully braked vehicle (stall test)

The purpose of this test is to measure the maximum engine speed with the output shaft of the automatic transmission fully braked on the ranges «D» And «R». Based on the test results, it is possible to determine the operability of the freewheel of the torque converter stator, as well as the presence of slip in the friction clutches and the first gear and reverse gear brake.

Attention! Do not allow anyone in front of or behind the vehicle during this check.

Check oil level and temperature (ATF) in an automatic transmission, as well as the temperature of the engine coolant. Oil level in automatic transmission (ATF) should be on the mark «NOT» on the oil dipstick. Oil in automatic transmission (ATF) must be warmed up to normal operating temperature (70–80°C). The engine coolant must also be warmed up to normal operating temperature (80–90°C).

Install the brake pads (chocks) under the rear wheels of the car.

Install a control tachometer to measure the engine speed.

Fully raise the parking brake lever and fully depress the brake pedal.


Start the engine.

Set the automatic transmission selector lever to position «D», fully depress the accelerator pedal to determine the maximum engine speed at that moment. During this test, do not hold the throttle fully open for longer than necessary to determine the maximum engine speed, or for more than five seconds. If this test needs to be carried out more than once, then after each test, move the automatic transmission selector lever to the position «N» and let the engine run at 1000 min^-1 for 2 min to cool the oil in the automatic transmission (ATF) between checks.

Rated value: engine speed with a fully braked vehicle (Stall test): 2300-2700 rpm

Move the selector lever to position «R» and repeat the test with the vehicle fully braked, similar to the points mentioned above.

When checking for a range «D» on a fully braked vehicle, the engine speed is greater than the nominal value

Exceeding the rated value of the engine crankshaft speed indicates slipping of the rear clutch or overrunning clutch of the gearbox. In this case, check the pressure in the automatic transmission control hydraulic system to determine the cause of slippage.

When checking for a range «R» on a fully braked vehicle, the engine speed is greater than the nominal value

Exceeding the rated value of the engine speed crankshaft indicates slippage of the front clutch of the gearbox or the brake of the first gear and reverse gear. In this case, check the pressure in the automatic transmission control hydraulic system to determine the cause of slippage.

When checking for a range «N» on a fully braked vehicle, the engine speed is less than the nominal value

If the engine speed is less than the nominal value, then the reason for this is insufficient (inadequate) engine output or torque converter failure. Check for misfires in the cylinders (misfire), ignition timing, valve clearance, etc. If no faults are found in all of the listed points, then the torque converter is faulty.