What are the reasons for the humming noise when the transmission bearing is damaged?
3 Answers
The reasons for the humming noise when the transmission bearing is damaged are: 1. Abnormal gear meshing clearance; 2. Gear tooth surface metal peeling, tooth breakage, or misalignment during assembly; 3. Insufficient lubrication due to lack of lubricating oil; 4. Water ingress into the transmission without timely repair, which may lead to abnormal noise over time; 5. Loose bolts on the transmission housing; 6. Excessive clearance between the gearshift lever and the shift fork groove in a manual transmission; 7. Use of inferior automatic transmission fluid. The functions of the transmission are: 1. To change the transmission ratio; 2. To expand the torque and speed of the driving wheels; 3. To enable the vehicle to reverse; 4. To facilitate gear shifting or power output in the transmission.
There are several main reasons why a faulty transmission bearing produces a humming sound. I've seen many such issues in the repair shop: when the balls inside the bearing wear out or break, friction increases during operation, and metal friction creates the humming noise. Insufficient or aged lubricating oil can also exacerbate friction, making the sound more noticeable as the transmission heats up. Sometimes, improper installation leads to uneven force distribution on the bearing, causing problems over time. The humming sound usually varies with vehicle speed, becoming more pronounced during acceleration or uphill driving. It's advisable to address the issue early; otherwise, it may damage gears or synchronizers, leading to higher repair costs. Regularly checking the transmission oil and maintaining clean lubrication can prevent such problems.
My car used to have a whining noise from the transmission, which was particularly annoying while driving, especially when accelerating above 70 km/h. When I took it to the repair shop, the mechanic said the bearing was broken, and the small balls inside were crushed, causing excessive clearance, which resulted in the whining sound from rotational vibration. He also explained that failed or water-contaminated lubricant would accelerate wear, which is more common in older cars. After replacing the bearing, it became much quieter. Now, I make sure to change the oil regularly to avoid further issues. Ignoring it could lead to solenoid or control module failures, which can be quite dangerous at high speeds.
