What Causes Abnormal Noise in the Transmission?
4 Answers
When bearings fail to operate normally, they can produce abnormal sounds. Below is relevant information: Transmission: A device that changes the speed ratio and direction of motion. It is used in automobiles, tractors, ships, machine tools, and various machines to alter the torque, speed, and direction of motion transmitted from the driving shaft to the driven shaft under different working conditions. A gear-driven transmission typically consists of a housing and several gear pairs. Automobile: According to the latest national standard in China, 'Terms and Definitions of Vehicle and Trailer Types,' an automobile is defined as a non-track vehicle powered by an engine, with four or more wheels, primarily used for: transporting people and/or goods; towing vehicles that carry people and/or goods; and for special purposes.
I've been driving for almost twenty years, and transmission noise is quite common. There are usually several possibilities: insufficient or aged fluid is the most basic cause—lack of lubrication leads to increased friction between components, resulting in a humming sound. For manual transmissions, worn clutch plates often produce a squeaking noise. In automatic transmissions, damaged synchronizers or gears commonly cause harsh clunking sounds during gear shifts. Bearing failure is another frequent issue, especially on bumpy roads. More serious problems, such as loose internal components or electronic control module failures, require professional diagnosis. I recommend first checking the transmission fluid yourself—if it appears black or contains debris, it's time for a change. Don’t delay, as these noises can lead to costlier repairs or even driving hazards. Regular transmission maintenance, like inspections every 50,000 kilometers, can effectively prevent such issues.
In the workshop, I frequently deal with transmission failures, where the causes of abnormal noises vary widely: simpler ones like low oil level causing the oil pump to whine, or expired fluid accelerating wear; more complex cases like bearing damage producing a continuous whining sound, or gears not meshing smoothly causing a clunk during gear shifts. Issues with the valve body or TCU in automatic transmissions can lead to intermittent noises. Don't forget about noises caused by loose chassis mounts or external impacts, which are also quite common. I always remind customers not to ignore minor sounds—recording them with a phone can help with analysis. Driving directly to the repair shop for a diagnostic check is the safest approach to prevent small issues from turning into major problems. Regular oil changes are a money-saving tip, by the way.
Our car's transmission has been making strange noises recently, and I'm starting to get worried. Since I use it to pick up and drop off the kids, safety is my top priority. I first checked the user manual and learned how to check the fluid level—pull out the dipstick to see if it's within the standard range, and add new fluid if it's low; if the fluid is discolored or has a burnt smell, it needs to be replaced immediately. Common sounds like a clattering noise might indicate gear issues, while a grinding noise suggests bearing wear. I didn't dare to fix it myself, so I directly booked an appointment at the dealership. The technician said it's likely a problem with the oil pump or synchronizer. Driving habits also affect this—sudden acceleration increases the risk of strange noises. Regular maintenance can save a lot of trouble, so now I get it checked every six months.
