What Happens When Transmission Fluid Gets Dirty?
2 Answers
It will significantly affect the lifespan of various components. Below are the consequences of dirty transmission fluid: 1. Firstly, the aging and degradation of the fluid will reduce the wear resistance of internal transmission components, greatly impacting their lifespan. Secondly, the sludge and impurities in the dirty fluid will increase the wear on friction plates and other components, and also affect the system's oil pressure, thereby hindering power transmission. 2. The sludge and impurities in the dirty fluid can obstruct the flow of oil in the valve body and oil pipes, affecting oil pressure. This can result in slow acceleration or failure of the automatic transmission. In severe cases, it may even cause a lack of oil pressure in a certain gear, leading to burnt friction plates and loss of power transmission. Therefore, vehicle owners should pay attention to maintenance and fluid replacement. Different car manufacturers have varying replacement intervals for their brands, so refer to your vehicle's manual and replace the fluid when due. Generally, the replacement mileage is between 40,000 to 60,000 kilometers, or if the vehicle has been idle for over a year. If the vehicle is used under harsh conditions, it is essential to replace the transmission fluid ahead of schedule based on the maintenance time and mileage.
If the transmission fluid gets dirty, the impact can be significant. I might notice that the car shifts roughly, often hesitating during upshifts or downshifts, making the driving experience uncomfortable. The reason is that too much metal debris and contaminants accumulate in the fluid, reducing lubrication effectiveness and increasing friction. Over time, the gears and clutch wear out severely. The temperature may also rise, causing the transmission to overheat, emit smoke, or produce strange noises. If the fluid isn’t changed promptly, minor issues can escalate into major problems—repairs costing thousands of dollars would be the least concern, and in severe cases, the entire transmission could fail. I recommend checking it every two years or 40,000 kilometers, along with replacing the filter, as prevention is far cheaper than repairs. Driving gently, avoiding rapid shifts, can also help keep the transmission fluid clean.
