The selection of hydraulic oil for the truck tailboard mainly depends on the working environment and working conditions of the tailboard hydraulic system, as well as the characteristics of the hydraulic oil. Regarding the choice of hydraulic oil No. 46 or No. 68, the following aspects can be considered:

　　1、 Viscosity performance

　　Hydraulic oil No. 46: With relatively low viscosity, it is suitable for use in low temperature or environments that require rapid flow. In the hydraulic system of the truck tailboard, if the working environment temperature is low or hydraulic oil needs to respond quickly to meet the lifting and lowering requirements of the tailboard, No. 46 hydraulic oil may be a better choice.

　　Hydraulic oil No. 68: With high viscosity, it is suitable for use in high temperature or environments that require high pressure. If the hydraulic system of the truck tailboard needs to operate at higher temperatures or withstand greater working pressures, hydraulic oil No. 68 may be more suitable.

　　2、 Pour a little

　　The pour point of hydraulic oil refers to the temperature at which it begins to lose its fluidity. For the tailboard of a truck, if there is a large temperature difference in the working environment, especially if it needs to be used in cold regions, it is more important to choose hydraulic oil with a lower pour point (such as certain specific models of 46 or 68 hydraulic oil) to ensure normal use even at low temperatures.

　　3、 Other performance

　　In addition to viscosity and pour point, the wear resistance, oxidation resistance, flash point, and other properties of hydraulic oil also need to be considered. Generally speaking, whether it is No. 46 or No. 68 hydraulic oil, it should perform well in terms of wear resistance and oxidation resistance to meet the needs of the hydraulic system for the truck tailboard.

　　4、 Specific selection suggestions

　　Choose according to the working environment temperature: If the working environment temperature is low, it is recommended to choose hydraulic oil with a lower pour point, such as certain specific models of No. 46 hydraulic oil; If the working environment temperature is high or requires significant working pressure, hydraulic oil No. 68 may be more suitable.

　　Consider the requirements of the hydraulic system: The specific requirements for hydraulic oil in the truck tailgate hydraulic system may vary depending on the vehicle model, manufacturer, and usage conditions. Therefore, when choosing hydraulic oil, it is best to refer to the recommendations of the vehicle manufacturer or consult professional opinions.

　　Pay attention to the replacement cycle of hydraulic oil: Regardless of which type of hydraulic oil is selected, it needs to be replaced regularly to ensure the normal operation of the hydraulic system. In general, it is recommended to set the replacement cycle according to the vehicle manufacturer's recommendations or the instructions for using hydraulic oil.

　　In summary, the selection of hydraulic oil for truck tailboards should be determined based on specific working environments and operating conditions. When unable to determine a specific choice, it is recommended to consult a professional or refer to the recommendations of the vehicle manufacturer.