What are the effects of not changing transmission fluid for a long time?
2 Answers
If the transmission fluid is not changed for a long time, it will accelerate the wear of the transmission and may even cause damage to the transmission's shift control mechanism. For manual transmissions, prolonged failure to change the transmission fluid can lead to difficulty in shifting. Automatic transmissions have shift control mechanisms that require transmission fluid to function properly. When changing the transmission fluid, it is essential to go to a professional service center and use specialized equipment. There are two methods for changing transmission fluid: the gravity drain method and the machine flush method. If the transmission fluid is not changed for an extended period, it will become increasingly viscous, impairing heat dissipation and causing excessive temperatures. Over time, this will affect the transmission's lifespan.
As a veteran driver with over 20 years of experience, I've learned many maintenance lessons the hard way. The most severe consequence of not changing transmission oil for extended periods is insufficient lubrication, which accelerates wear on internal gears and bearings, causing abnormal noises or jerky shifting. When the oil deteriorates and thickens, its cooling efficiency drops, making the transmission prone to overheating—sometimes even triggering protective shutdowns. Once I procrastinated until 60,000 km to change the oil, resulting in loud noises, 10% increased fuel consumption, and ultimately thousands in parts repairs. Long-term neglect also allows sludge buildup that clogs oil passages, reducing transmission efficiency and potentially causing premature failure. Regularly check the oil's color and smell—changing every 40,000 km or two years saves money and ensures safety.
