Replace the filter in time according to the filter replacement cycle provided in the maintenance manual. At the same time, clean the filter screen, the oil drain magnet screw plug, and the vent plug, and add the standard amount of lubricating oil. If the viscosity of the transmission oil is too high, it will cause low transmission efficiency, poor fluidity, and unfavorable heat dissipation, and there may be local dry friction between the relatively moving parts at high speed, which is unfavorable for lubrication; if the viscosity of the transmission oil is too small, It can increase the leakage, cause the transmission control oil pressure to be too low, cause failures, and the oil film strength between the transmission parts with heavier load is not enough, which causes the early wear of the transmission parts, which is also unfavorable for lubrication.