What is the Function of Transmission Fluid in Cars?
3 Answers
Transmission fluid functions to reduce friction, minimize wear, bear loads (low-speed high torque, vibration loads), dissipate heat, reduce vibration and noise, and prevent corrosion. The methods for changing transmission fluid and the effects of prolonged non-replacement are as follows: Methods for Changing Transmission Fluid: There are two methods for changing transmission fluid: gravity drain and machine flush. The machine flush method is recommended because it can clean the transmission, whereas the gravity drain method only replaces the fluid without cleaning. Effects of Not Changing Transmission Fluid: Failure to change transmission fluid can lead to thickening of the fluid, reduced oil pressure, obstructed internal heat dissipation, and excessively high oil temperatures, thereby shortening the lifespan of the transmission and drivetrain components. Without changing the transmission fluid, the vehicle may experience sluggish acceleration and frequent slipping during driving. Prolonged non-replacement can cause the transmission fluid to degrade and evaporate under high-speed and high-temperature conditions, leading to rapid wear and damage to internal transmission parts.
Transmission fluid is as vital to a car as blood is to the body - something I've deeply understood after driving my car for so many years. It not only lubricates the gears inside the transmission, preventing them from grinding and wearing against each other with annoying clunking sounds, but also helps with heat dissipation. Just imagine - transmission temperatures can soar over 100°C during operation, and without this fluid for cooling, components would surely burn out. Additionally, it performs cleaning functions, washing away metal particles shed during gear meshing. Automatic transmission vehicles rely on it even more, as this fluid is solely responsible for power transfer during gear shifts. My recommendation is to inspect and replace it every 40,000-60,000 km, otherwise you might suddenly find yourself unable to shift gears one day, and the towing fees alone could cover multiple fluid changes.
My first encounter with gearbox oil was during an internship at a repair shop, where the master mechanic explained its principles to me. This oil primarily serves three major functions: lubricating the gear system to reduce wear, much like applying grease to machine joints; cooling the transmission to prevent overheating, as mechanical friction generates significant heat; and crucially for automatic transmission vehicles, it transmits hydraulic pressure to enable smooth gear shifts. The internal structure of a gearbox is highly precise, containing various bearings and clutch plates, all protected by the oil film. I also learned that if the oil turns black or emulsifies, it must be replaced immediately, as accumulated metal particles can accelerate component wear.
