What Causes Abnormal Noise During Gear Shifting in the Transmission?
3 Answers
Here are the main reasons for abnormal noise during gear shifting in the transmission: 1. Transmission bearings often operate under high-speed and heavy-load conditions, enduring significant alternating loads. As a result, the rolling balls or cylindrical rollers and raceways of the bearings may experience wear, spots, fatigue spalling, or burning, leading to increased axial and radial clearance, which causes impact noise. 2. During gear meshing transmission, sliding friction exists from the tooth top to the tooth root, making wear inevitable. Due to gear wear, the meshing clearance increases, resulting in impact noise during vehicle operations such as starting or shifting gears. 3. After bearing wear causes looseness, shaft deformation or housing deformation alters the center distance between meshing gears and causes misalignment of axes; wear in the sliding keyways on the shaft and internal spline grooves of sliding gears; loose fastening bolts in the control mechanism and wear or deformation of the shift fork can lead to gear displacement. 4. Improper driver operation, such as aggressive starting or poor hand-foot coordination during gear shifting, can cause significant impact loads in the transmission, leading to broken or shattered gear teeth and abnormal noise.
After years of driving, transmission shifting noises are quite common. It could be due to the clutch not being fully depressed, causing misalignment of gears and resulting in a clicking sound. Alternatively, severely worn synchronizers can produce a jerking noise during gear shifts. If transmission fluid isn't changed for extended periods, the aging and contaminated fluid provides insufficient lubrication, leading to squeaky friction sounds during shifting. Additionally, damage to the gear set itself, such as small cracks or missing teeth, often becomes more noticeable when engaging reverse gear. For prevention, regularly check fluid levels, add fresh fluid during each oil change service, and don't ignore minor sounds - they can escalate into major issues. In summary, when abnormal noises occur, promptly pull over to a safe location for inspection to avoid driving in anxiety and ultimately facing costly transmission repairs.
As someone who enjoys tinkering with cars, I think transmission noise may have several sources. For manual transmissions, the most common issue is worn synchronizers, which cause a clunking sound when shifting gears. For automatic transmissions, it could be a stuck control valve or a faulty sensor, resulting in a buzzing noise. If the fluid level is too low or the fluid is dirty, insufficient lubrication can cause gears to operate roughly. External factors, such as improperly installed exhaust pipes during modifications, can also transmit vibrations that interfere with shifting. When troubleshooting, start with the simplest steps: check the fluid level and top it up if necessary; listen to the location of the noise to determine if it's coming from inside the transmission. Addressing the issue early can prevent more expensive repairs, as delaying may lead to complete transmission failure.
