The following are the key specific aspects of transmission gear:

1. Gear strength: Gear must have sufficient bending strength and contact strength to avoid fracture or surface contact fatigue under load.

2. Gear wear resistance: Because the gear works for a long time at high speed and high pressure, wear resistance is a necessary condition for the gear to reduce wear and extend service life.

3. Fatigue resistance: gear in the process of repeated loading and unloading, must be able to withstand fatigue load, to avoid fatigue failure.

4. Machining accuracy: The machining accuracy of the gear is directly related to the accuracy of the gear mesh, affecting the transmission efficiency and noise level of the gearbox.

5. Gear box matching: the gear must be well matched with other components in the gearbox to achieve efficient and smooth power transmission.

6. Environmental adaptability: the gear needs to adapt to various environmental conditions, such as high temperature, low temperature, humidity changes, etc., and can still maintain stable performance.

7. Maintenance and replacement: the maintenance and replacement of the gear is also the key, and a reasonable maintenance plan can ensure that the transmission gear is always in good working condition.

Through continuous technological innovation and material optimization, the performance and reliability of transmission gears are constantly improving to meet the higher performance and durability requirements of modern vehicles.