The clutch is switched on (with the pedal released) should not «slip» and without loss to transfer torque from the engine to the transmission, and with the clutch pedal depressed, completely disconnect the transmission from the engine. Engagement of the clutch should be smooth - without jerks.
Comment. Clutch test shown on a car with a manual transmission (ITUC). Checking the clutch on a car with an automated transmission is shown in the section «Automated transmission - checking the technical condition».
Execution sequence
1. We prepare the car for work (see «Preparing the car for maintenance and repair»).
2. With the engine off, press the clutch pedal several times. We make sure that there are no jams in the clutch release mechanism, that there are no squeaks, knocks and other extraneous noises.
3. We start the engine. If a howling sound is heard from the clutch housing, which increases when the clutch pedal is depressed, the clutch release bearing is most likely worn.
4. With the engine running, press the clutch pedal all the way and shift into gear. Switching on should be easy, without crackling or crunching. If a crackling sound is heard when shifting gears, and turning off is difficult, then the clutch is not completely disengaged. We pump the hydraulic clutch release. If there is no air in the drive, the defect may be caused by a malfunction of the clutch master cylinder, clutch slave cylinder, wear or a decrease in the elasticity of the diaphragm spring.
5. With the engine running and the first gear engaged, gradually releasing the clutch pedal, we check the smooth engagement of the clutch, the absence of jerks and extraneous sounds at the moment of starting. Jerks and chatter at the time of engagement of the clutch can be caused by oiling or warping of the clutch discs, or the destruction of the vibration damper.
6. In motion in third gear, sharply press the gas pedal. If the engine speed increases quickly and the vehicle accelerates sluggishly, the clutch will slip. This is also evidenced by the appearance in the cabin of the smell of burning, emitted by the highly heated friction linings of the driven disk. To fix this problem, you need to replace the clutch.
If the above symptoms of malfunctions are not detected during clutch diagnostics, the clutch is in a technically sound condition.