(1) Wear of the speed change transmission mechanism The W4-60 excavator adopts a mechanical shift transmission mechanism, which relies on the sliding tooth sleeve to move axially on the fixed tooth sleeve and is connected with the driven gear of each gear. engaged to achieve shifting. In the frequent shifting process, the tooth end faces of the above-mentioned meshing gears are easily ground into a conical shape, which reduces the meshing performance and leads to "jumping gears".

(2) The performance of the self-locking mechanism is degraded. In order to prevent the transmission from "jumping", this type of excavator is installed in the box cover holes above the fork shafts of the Ⅱ, Ⅲ and Ⅳ and Ⅴ gears of the transmission and in the Ⅰ and reverse shift forks. There are steel balls and springs that play a self-locking role. When the elasticity of the spring that plays the role of positioning and self-locking is weakened or broken, the self-locking performance of the self-locking mechanism will decrease until it disappears, causing the transmission to "jump". At the same time, if the groove on the positioning steel ball or the fork shaft is worn, it can also cause the transmission to "jump".

(3) Improper adjustment of the shifting device The transmission of this type of excavator adopts a mechanical manual shifting method. If the shifting lever, vertical axis, horizontal axis and vertical fixing screws are loose, the transmission can also "jump".

(4) Sudden change of external load Due to the working nature of the excavator and the design of the machine itself, the sudden change of the external load will also cause its transmission to "jump". When the road surface is uneven, the machine is driving downhill or the driving route is improper and the external load changes suddenly, the sudden change of the load will act on the gear meshing gear of the transmission through the wheels and drive shaft, so that the gear meshing gear Disengagement due to axial thrust, causing the transmission to "jump".

(5) Improper operation method When the excavator is driving on a slope (especially driving downhill), if the operation is improper, it will also cause the transmission to "jump".