What Causes Transmission Noise?
2 Answers
Transmission noise can be attributed to the following reasons: Presence of internal contaminants: In many cases, it's not due to damage to the internal valve body, but rather the accumulation of stubborn dirt and contaminants inside. Especially when these impurities gather in the valve body, they can form blockages that prevent effective regulation of oil pressure, leading to issues like jerking, impact, and slippage. Excessive transmission temperature: High temperatures can degrade the quality and frictional properties of automatic transmission fluid, increasing friction and wear, which results in transmission noise. Simultaneously, sludge forms inside the transmission, causing jerking and impact. If the temperature exceeds 120 degrees, rubber sealing materials begin to harden, eventually leading to leaks and reduced hydraulic pressure. At even higher temperatures, the transmission starts to slip, and this slippage further raises the temperature. If not addressed promptly, the transmission may become irreparably damaged.
I've driven trucks for many years and encountered many transmission noise issues. The most common is gear wear—after prolonged use, the teeth get worn down, making a terrible clunking sound when shifting. Insufficient lubrication is also a major problem; dirty or low fluid causes excessive friction between parts, making the noise more noticeable. Bearing damage isn’t uncommon, especially when the ball bearings age, producing a buzzing sound with vibrations. Synchronizer failure is also common, particularly during hard acceleration, resulting in a harsh screeching noise. Delaying repairs is risky—the entire transmission could fail, and breakdowns become more likely. I recommend finding a reliable mechanic for an inspection as soon as possible; don’t skimp on small costs. Regular oil changes and maintenance can prevent most issues—at least an annual check-up helps catch problems early. Safety first—don’t delay!
