How often should the transmission fluid be changed for a Mercedes 9AT?
2 Answers
Mercedes transmission fluid should be changed every three years or 60,000 kilometers, whichever comes first. Definition of Transmission Fluid: Transmission fluid is an oil product that keeps the gear system clean, ensuring the normal operation of the transmission and extending the lifespan of the transmission components. Function of Transmission: Transmission fluids are generally compatible with automatic transmissions on the market. In fact, each automatic transmission design has different technical requirements. Even the same model of transmission configured in different vehicle models may vary in torque, weight, speed, structure, etc. Therefore, the original manufacturer specifies its own dedicated transmission fluid. Different transmission fluids are one of the factors affecting shift quality.
The replacement interval for Mercedes-Benz's 9AT transmission fluid depends on the specific model and manual recommendations. Based on my experience servicing many such vehicles, it's generally advised to change it every 70,000 to 80,000 kilometers. However, frequent city driving in traffic or poor road conditions causing rapid oil temperature rise may accelerate aging, requiring replacement as early as 50,000 kilometers. Driving habits significantly impact this - steady highway cruising causes less wear compared to stop-and-go traffic. Delaying fluid changes can lead to sludge buildup causing gearshift hesitation, and severe cases may require costly transmission overhauls costing tens of thousands, which isn't economical. It's best to have professional shops inspect the fluid condition every 30,000 kilometers - address immediately if the fluid appears blackened or has a burnt smell.
