The replacement interval for automatic transmission fluid (ATF) should be determined based on transmission type, driving conditions, and the vehicle manual, typically recommended every 40,000 to 80,000 kilometres or 3 to 5 years. AT transmissions, with their mature design and stable fluid properties, can often extend to the upper limit under normal driving conditions. CVT transmissions, which depend on fluid for power transfer and require high cleanliness, should have the fluid and filter replaced every 40,000 to 60,000 kilometres. Wet dual-clutch transmissions, where the fluid serves both lubrication and cooling functions, may need replacement every 60,000 to 80,000 kilometres in high-temperature environments, while dry dual-clutch transmissions, with lower gear lubrication demands, can extend to around 100,000 kilometres. Prolonged use in congested traffic (average speed ≤30 km/h), aggressive driving, or heavy loads accelerates fluid oxidation, necessitating a 20%-30% shorter replacement interval-for example, reducing a 60,000-kilometre interval to 42,000 kilometres. Additionally, high temperatures or dusty conditions hasten fluid degradation, so the initial replacement should not exceed 30,000 kilometres. For replacement methods, gravity drainage (60%-70% fluid exchange) is advised for new vehicles, while a flush machine (over 90% exchange) may be used for older or heavily contaminated transmissions, provided the fluid meets OEM specifications. Owners should use the manual as a baseline, adjusting intervals based on driving conditions and fluid condition to maintain transmission performance and minimize repair risks.
