Does Car Transmission Fluid Need to Be Replaced?
2 Answers
Car transmission fluid needs to be replaced. Transmission fluid is a consumable item. During the use of a car, friction in the transmission generates fine debris and impurities, causing the transmission fluid to become turbid and its performance to degrade. This can affect the operation of the transmission and lead to driving issues. Generally, transmission fluid is red in color, and over time, the color gradually darkens. When it turns black, it must be replaced. The methods for replacing transmission fluid are as follows: Gravity Drain: Typically, only 3 to 5 liters of transmission fluid need to be added. The drawback is that gravity draining doesn't remove all the old fluid, only about one-third of the original fluid. Machine Flush: A transmission flush machine is connected to the transmission's fluid lines, and new fluid is added to the machine. The new fluid then "pushes" out the old fluid from the transmission. The advantage is a thorough replacement, but the process is time-consuming and more expensive. Transmission Pan Removal: The benefit is that the transmission filter can be cleaned, and the replacement is more thorough. The downside is that the procedure is overly complicated.
As a seasoned mechanic with years of experience in auto repair shops, I firmly believe that transmission fluid does require regular replacement. Transmission fluid serves as both the lubricant and coolant for the entire transmission system, protecting gear sets while reducing friction and heat buildup. If left unchanged for extended periods, the fluid accumulates metal particles and contaminants, loses viscosity, and fails to provide protection. This leads to rough shifting, strong jerking sensations, or even transmission overheating and failure. Manufacturers recommend replacing automatic transmission fluid every 40,000–60,000 km or two years, while manual transmissions have slightly longer intervals. The inspection method is simple: use the dipstick to check the fluid's color—fresh fluid appears clear red, whereas darkened fluid or fluid with a metallic odor indicates replacement is due. Neglecting this maintenance may result in transmission repairs costing thousands, which is simply wasteful. Develop the habit of having technicians inspect fluid conditions during routine servicing to maintain smooth vehicle performance.