Why does the abnormal noise disappear when the clutch is depressed?
2 Answers
When the clutch is depressed, the rear bearing of the transmission's first shaft and the front needle roller bearing of the second shaft stop rotating, causing the abnormal noise to naturally disappear. Below are the reasons for abnormal noises in the transmission: 1. Wear and damage of bearings: When bearings wear out, the clearance increases and the fitting accuracy decreases; when bearings are damaged, abnormal noises occur as they cannot operate normally, potentially leading to damage of transmission components and exacerbating the issue. 2. Wear of transmission components or the use of replacement parts with excessively low precision: Excessive clearance due to gear wear or mismatched replacement gears. 3. Insufficient or overly viscous lubricant causing poor lubrication: Replace the appropriate lubricant (grease), otherwise it will accelerate transmission wear and shorten its service life.
I often encounter this issue at the repair shop. When you press the clutch pedal, it becomes quiet, which is mostly due to a faulty release bearing. The clutch release bearing rotates against the pressure plate, and when it's severely worn, it makes a rattling noise. When you depress the clutch, the pressure plate disengages, the bearing is no longer under load and stops rotating, so the noise naturally disappears. If it's an older car, you might also want to check if the clutch fork lacks grease. Delaying repairs is not an option. If the bearing seizes up one day, even shifting gears will become difficult. I've seen a car owner who stubbornly endured it for half a year, and in the end, the entire pressure plate had to be replaced, costing several thousand more. Early inspection saves worry and money, and avoids the hassle of breaking down on the road.
