Transmission fluid replacement is one aspect of car maintenance that is frequently overlooked. Unlike changing your oil, you don’t have to change your transmission fluid very often. Depending on the model of car you own, you may never need to do it. The lack of a transmission dipstick indicates these transmissions. They’re sealed for good. However, most transmissions necessitate fluid replacement on a regular basis.

Even if the transmission case is never opened, transmission fluid can become contaminated. Metal flakes from the gears, moisture that gets into the transmission, and non-metallic, heat-resistant material from internal parts can all contaminate the fluid.

Transmission fluid should be changed at different intervals according to the manufacturer. Consult your owner’s manual for the recommended kilometers between transmission fluid changes. Automatic transmission fluid should be checked once a month, in general, to prevent problems from developing (the condition of the fluid can be visually observed on the dipstick—contaminated fluid will look dirty and smell burned). For a manual gearbox, every 48,000 to 80,000kms the fluid should be replaced. If you’re changing your transmission fluid yourself, make sure you use the right kind. There are various types.

Transmission fluid lubricates the internal parts of the transmission (gears, clutches, and so on). This action prevents the transmission components from overheating. If the vehicle is equipped with a transmission cooler, the transmission fluid can also serve as an indirect part of the cooling system.

The operation of a car would be impossible without transmission fluid, at least not at the speed and efficiency to which we have grown accustomed. Transmission fluid, like so many other modern marvels, serves a purpose that essentially (and literally) keeps the wheels turning, but many people are unaware of it.

Will your transmission fail if the fluid isn’t changed? Perhaps not. But one thing is certain: contaminated fluid is responsible for a higher percentage of failed transmissions than fluid that has been replaced. Transmission repairs are expensive, so it seems reasonable to ensure that transmission fluid maintenance is performed on a regular basis, even if it’s just to pull up the dipstick and check the fluid’s condition.