What Causes the Abnormal Noise in a Manual Transmission?
2 Answers
Manual transmission abnormal noise is caused by: 1. Severe wear of internal friction plates, resulting in uneven surfaces that cause jerking and abnormal noise during contact; 2. Severe wear of the plungers inside the car's valve body; 3. Lack of lubricating oil or deterioration of lubricating oil leading to noise; 4. Incomplete clutch separation, causing abnormal noise in the transmission. Solutions for manual transmission abnormal noise: 1. Adjust the clutch pedal and replace the pressure plate; 2. Add oil or check oil quality; 3. Repair or replace loose and damaged bearings. Common faults of manual transmissions in cars are the transmission slipping out of gear or failing to engage while driving, preventing the car from moving.
I've encountered strange noises when driving a manual transmission car several times myself. The most common is a clicking or grinding sound when shifting gears, often due to low or aged transmission oil. After prolonged use, oil leaks or gets contaminated with metal particles, reducing lubrication effectiveness, causing gears to scrape against each other and make noise. Another common cause is worn synchronizers, which help gears engage smoothly during shifts—when worn, they tend to produce clicking sounds. If the noise appears during idle, the issue is more serious, possibly due to loose bearings or cracked gears. During my last inspection, the mechanic warned that ignoring these sounds could lead to severe breakage accidents and affect fuel efficiency. So, upon hearing unusual noises, it's best to stop and check the oil level or take it to a professional shop immediately—manual transmissions are complex, and DIY fixes often don't work.
