The transmission efficiency of automobile transmission shaft is influenced by many factors, mainly including the following:

1. Lubrication: The lubrication of the transmission shaft directly affects the transmission efficiency. Good lubrication can reduce the friction resistance of transmission system and improve transmission efficiency. If the lubricating oil is insufficient or of poor quality, it will increase the friction resistance and reduce the transmission efficiency.

2. State of transmission shaft bearing: The wear degree of transmission shaft bearing will affect the transmission efficiency. A badly worn or loose transmission shaft bearing will increase friction resistance and reduce transmission efficiency.

3. Design and manufacturing quality of transmission shaft: The design and manufacturing quality of transmission shaft directly affects the transmission efficiency. If the design of the transmission shaft is unreasonable or the manufacturing quality is not up to standard, the transmission efficiency will be affected.

4. Steering angle: When the vehicle turns, the transmission shaft will be subject to certain angle changes. Excessive steering angle will increase the friction resistance of the transmission system and affect the transmission efficiency.

5. Load condition: The vehicle load condition will also affect the transmission efficiency of the transmission shaft. Excessive load will increase the load of the transmission system and reduce the transmission efficiency.

6. Tire condition: The air pressure of the tire, the degree of wear, the contact between the tire tread and the ground and other factors will affect the transmission efficiency of the transmission shaft. Uneven tire wear or insufficient tire pressure will lead to a decrease in transmission efficiency.

To sum up, lubrication, bearing condition of transmission shaft, design and manufacturing quality of transmission shaft, steering angle, load condition and tire condition will all affect the transmission efficiency of automobile transmission shaft. Therefore, regular inspection and maintenance of the transmission system of the transmission shaft, keeping good lubrication condition, bearing condition and tire condition of the transmission shaft, choosing suitable road surface, and reasonably controlling the steering angle and load are all helpful to improve the transmission efficiency of the transmission shaft and ensure the normal operation of the vehicle.