What Causes the Abnormal Noise in CVT Transmissions?
2 Answers
Here are the specific reasons for abnormal noise in CVT transmissions: Presence of internal contaminants: In many cases, abnormal noise in CVT transmissions is not caused by damage to the internal valve body but by stubborn dirt and contaminants inside, especially when dirt and contaminants accumulate in the valve body, forming blockages that prevent effective regulation of oil pressure, leading to jerking, impact, and slippage issues. Excessive transmission temperature: High temperatures can degrade the quality and friction characteristics of automatic transmission fluid, increasing friction and wear, which results in transmission noise. Additionally, sludge can form inside the transmission, causing jerking and impact. If the temperature exceeds 120°C, rubber sealing materials begin to harden, eventually leading to leaks and reduced hydraulic pressure. At even higher temperatures, the transmission may start to slip, and this slippage can further raise the temperature. If not addressed promptly, the transmission may be irreparably damaged.
CVT transmission noise can have various causes, and I often hear car owners complaining about such issues. The core structure of a CVT transmission is the steel belt and pulley system. Once these components wear out or slip, they can produce abnormal noises like humming or rustling, especially during acceleration or deceleration. My suggestion is to first check the transmission fluid—low fluid levels or deteriorated oil can lead to insufficient lubrication, increasing friction and noise. Additionally, aging of the chain or steel belt can also cause sounds, especially after the car has been driven for several years. If the problem persists, it might be due to wear in internal components, such as damage to the driving or driven pulleys, requiring professional diagnosis. When driving, avoid sudden acceleration and ensure regular maintenance, including oil changes, to prevent this issue. After all, CVT transmissions are costly to replace, so early repairs can save you from expensive overhauls later.
