Selecting the right gear oil is crucial for ensuring optimal performance, longevity, and efficiency of mechanical systems. Key factors to consider include viscosity grade, which affects lubrication and load-bearing capacity, and additive composition, which enhances wear protection, corrosion resistance, and thermal stability. Operating conditions, such as temperature extremes and load intensity, also play a vital role in determining the appropriate oil type. Additionally, compatibility with seals and materials, as well as industry-specific requirements, should be assessed to prevent premature wear and system failures. Choosing the right gear oil enhances equipment reliability, reduces maintenance costs, and improves overall performance.