Testing is performed to determine the maximum engine speed when the selector lever is in the "D" or "R" positions, and to check the operation of the torque converter, starter and one-way clutch, as well as the performance of the clutches and brakes.
Warning: No one should stand in front or behind the vehicle while testing is being performed.
Procedure
1. Before testing, check the levels of all operating fluids and, if necessary, top them up to normal.
- The transmission fluid level should be near the "HOT" mark on the gauge.
- The transmission fluid temperature should be between 80–100°C.
- Coolant temperature 80–100°C.
2. Place chocks under the rear wheels.
3. Apply the parking brake and press the brake pedal.
4. Start the engine.
5. Move the selector lever to the "D" position. Press the brake pedal fully with your left foot and gently press the accelerator pedal with your right foot. When the engine speed no longer increases, read the tachometer and release the accelerator pedal.
- 1. To avoid damage to the gearbox, perform testing for 8 seconds.
- 2. If more than one test is required with the engine running, move the selector lever to the "N" position and let the engine run at idle speed until the transmission fluid has cooled. Running the engine at idle speed cools the transmission fluid and prevents its properties from deteriorating.
- 3. Carry out the test in the same manner with the selector lever in position "R".
Warning! Engine speed when testing automatic transmission and engine operation together on a stationary vehicle (stall test):
- F4A42: 2000–2900 min⁻¹
- A4AF3: 2200-2800 min⁻¹
Warning! Engine speed during F4A42 automatic transmission and engine operation testing on a stationary vehicle (stall test): 2000–2900 min⁻¹
Analysis of test results
1. Engine speed is higher than specification in "D" and "R" position.
- Low pressure in the pipeline.
- Slipping of brake bands in low gear and reverse gear.
2. Engine speed is above specification only in "D" position.
- Downshift clutch slipping.
3. If the engine speed is above specification only in the "R" position.
- Reverse clutch slipping.
4. If the engine speed is below the specification in the "D" and "R" positions.
- Damage to the torque converter.
- Insufficient engine power.