Sequence of execution
1. We make sure that the automatic transmission control system is working properly by turning on the ignition. Then, pressing the brake pedal, move the selector lever in turn to all positions, while the corresponding symbols should be displayed on the information display. After that, return the selector lever to position N ("neutral").
2. Start the engine. If you hear a whining sound coming from the clutch housing, the clutch release bearing is likely worn out. A similar sound can be caused by worn gearbox bearings.
3. Keeping the brake pedal pressed, we switch the selector in turn to all positions, while making sure that the gear shift mechanism is working properly. The switch should be easy to turn on, without any crackling or crunching sounds.
Note: If there is a howling sound when disengaging the clutch (see above p. 2) intensifies - the clutch release bearing is worn out. If the sound disappears, the gearbox bearings are worn out. If you hear a crackling sound when shifting gears and the car jerks, it means that the clutch is not disengaging completely. The cause may be a malfunction of the gear shift mechanism, wear or loss of elasticity of the clutch diaphragm spring, or a malfunction of the clutch release electric drive. To check the gearshift mechanism and the electric clutch release drive, it is necessary to check the fault codes stored in the transmission control unit, so this work should be carried out at a specialized service station with the necessary equipment.
4. Set the selector lever to position N ("neutral"). Release the brake pedal, but the car should not start moving.
5. Check the operation of the gearbox while driving. To do this, turn on mode A (forward movement in automatic mode) and slowly press the gas pedal. The clutch should engage smoothly. We move first with acceleration, and then with deceleration, we make sure that the clutch engages smoothly, and that gears shift smoothly (both upward and downward), in the absence of crunching, knocking and other extraneous sounds from the gearbox.
6. Turn on the M mode and repeat the test by shifting gears in manual mode. To do this, move the selector lever first towards the "+" symbol, and then towards the "-" symbol. The gearbox should work without failures, shifting gears in the selected direction.
7. Stop the car and move the selector lever to position R. After releasing the brake pedal, the car should begin to move backward.
Comment:
- Jerks and rattling when the clutch is engaged can be caused by oiling or warping of the clutch discs or destruction of the torsional vibration damper.
- Untimely gear shifting, or engaging a gear that is not appropriate for the driving speed, is caused by a malfunction of the transmission control unit.
- Jerks and delays when shifting gears while the vehicle is moving, or engaging gears with a shock may indicate a malfunction of the gear shift mechanism or the electric clutch release drive. Troubleshooting such problems requires reading the fault codes stored in the transmission control unit, so this work should be performed at a specialized service station with the necessary equipment.
- In addition, when replacing a faulty electric drive mechanism, it is necessary to adjust the transmission control system. Otherwise, correct operation will be impossible.
Recommendation. If it is not possible to restore the functionality of the gear shift mechanism or the electric clutch release drive (for example, due to lack of spare parts), then the gearbox can be converted to manual control. To do this, it is necessary to dismantle the specified parts and install a gear shift mechanism with a cable drive, as well as a clutch release cable.
8. When driving in third or fourth gear, press the gas pedal sharply. If the crankshaft speed increases quickly and the car accelerates sluggishly, the clutch is slipping.
Note: Clutch wear may also be indicated by the appearance of a burning smell in the cabin, emitted by the very hot friction linings of the driven disk. In this case, it is necessary to replace the clutch.
9. Prepare the car for further work (see "Preparing the car for maintenance and repair") and install it on an inspection ditch or overpass.
8. Remove the engine crankcase guard and engine splash guard (if installed).
9. Inspect the gearbox from all sides and make sure there are no transmission oil leaks.
Recommendation. If leaks are detected on the gearbox housing, the transmission oil level should be checked and, if necessary, the oil level should be brought up to normal.