Transmission fluid
The transmission fluid is responsible not only for lubricating the gearbox, but also to cool it. Wear and tear of this liquid may change its parameters such as viscosity and consequently, lead to damage of other components. To make sure your gearbox works seamlessly, remember to have it replaced as often as advised by your car’s manufacturer.
For instance, Audi recommends performing the service schedule of the transmission fluid every 38,000 miles. But in case your gearbox is exposed to some unusual working conditions, it may need to be looked upon more often. Make sure to visit a specialised workshop for professional advice in order to avoid any problems with your car.