What Causes the Buzzing Sound on the Left Side When the Lavida Shifts to Sixth Gear?
4 Answers
Lavida shifting to sixth gear with a buzzing sound on the left side may indicate a transmission malfunction. Dirty valve body causing transmission malfunction: A dirty transmission valve body can degrade the quality and friction characteristics of the transmission fluid. This increases friction and wear, and sludge can also form inside the transmission, leading to blockages in the valve body and pipelines. As a result, the regulation of oil pressure becomes disordered, causing transmission issues. Engine overheating leading to transmission malfunction: High temperatures can damage the quality and friction characteristics of automatic transmission fluid, increasing friction and wear, which leads to transmission noise. Additionally, sludge (contaminants or dirt) can form inside the transmission (such as in the valve body), causing jerks or shocks during gear shifts. If the temperature exceeds 120 degrees Celsius, 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 slipping can further raise the temperature, exacerbating the problem.
I also encountered a similar issue when I first drove my Lavida. The buzzing noise on the left side in sixth gear was quite annoying. Later, I found out it might be due to wear on the left front wheel bearing—the noise becomes more noticeable as the speed increases. However, uneven tire wear can also cause this, as uneven tread patterns can easily resonate and produce a buzzing sound. Additionally, wear on the driveshaft universal joint is another common cause, especially in older cars with over 70,000-80,000 kilometers. I once tried coasting in neutral to listen for changes in the noise—if it's a bearing issue, the noise persists even when coasting, ruling out engine-related causes. But I’ve also had similar problems from a loose underbody shield; when the screws came loose over bumps, it would rattle. I recommend getting it checked as soon as possible—if it’s a bearing issue, continuing to drive could compromise safety.
Last week, my friend's 2019 Lavida also reported this issue. I took a look for him and found that besides the bearing problem, it could also be resonance caused by a loose transmission bracket or aging engine mounts. That humming noise tends to increase or decrease with changes in vehicle speed. Additionally, a poorly installed aftermarket underbody shield can generate low-frequency resonance at high speeds, sounding like noise coming from the front left. There's also a small chance it could be due to deformed air conditioning blower fan blades, though this would be more noticeable when the AC is turned on. It's best to conduct a comprehensive inspection when troubleshooting to prevent minor issues from escalating.
Don't ignore such humming sounds. I've experienced the terrifying situation of sudden bearing seizure while driving a Lavida. Apart from common wheel hub bearing issues, it could also be abnormal noise caused by wear of the left front suspension ball joint, especially more noticeable during turns. Aging of the front-wheel drive half-shaft bushings can also produce a metallic friction-like hum, a consequence of prolonged use leading to rubber component cracking. Insufficient transmission oil causing dry grinding of gears may also result in noise at specific gears. Focus on checking the transmission dipstick fluid level and bearing clearance.
