What Causes Slipping in Automatic Transmissions?
2 Answers
When an automatic transmission experiences slipping, it is often not due to internal valve body damage, but rather the accumulation of stubborn dirt and impurities inside, especially when these contaminants gather within the valve body, forming blockages that prevent effective regulation of oil pressure. This leads to issues such as jerking, impact, and slipping. Below are the key points: 1. Transmission Overheating: Transmission overheating is a significant concern. High temperatures degrade the quality and frictional properties of automatic transmission fluid, increasing friction and wear, which results in transmission noise. Additionally, sludge (impurities or dirt) can form inside the transmission (e.g., in the valve body), 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 starts to slip, and slipping further raises the temperature. 2. Solution: To completely resolve transmission issues and prevent recurrence, it is essential to remove stubborn dirt and impurities from the transmission and effectively control the transmission's operating temperature.
I've been driving automatic transmissions for over a decade, and most slippage issues are caused by transmission fluid problems. Deteriorated fluid, insufficient oil level, or using inferior quality oil can all affect the hydraulic system's operation. When the fluid ages, its viscosity changes, directly impacting the torque converter's power transfer efficiency. Additionally, a clogged transmission filter is a hidden culprit that can cause abnormal oil pressure, preventing the clutch plates from fully engaging. Last time I encountered a similar situation, the slippage was accompanied by metallic grinding noises. Upon disassembly, we found the clutch plates had worn down to bare metal. In such cases, you must completely replace both the transmission fluid and filter. Continuing to drive could lead to planetary gearset failure, and the cost of replacing an entire transmission is far higher than just changing the fluid.
