(1) The W4-60 excavator adopts a mechanical shifting and variable speed transmission mechanism, which relies on the sliding gear sleeve to move axially on the fixed gear sleeve and mesh with the driven gears of each gear to achieve shifting. During frequent gear shifting, the tooth end faces of the meshing gears mentioned above are prone to grinding into cones, resulting in a decrease in their meshing performance and causing gear shifting.
(2) The performance of the self-locking mechanism decreases. In order to prevent the transmission from shifting, this type of excavator is equipped with steel balls and springs that play a self-locking role in the box cover holes above the shift forks for gears II, III, IV, and V of the transmission, as well as in the shift forks for gears I and reverse. When the elasticity of the spring that plays a positioning self-locking role weakens or breaks, the self-locking performance of the self-locking mechanism will decrease until it disappears, causing the transmission to "jump gears". At the same time, if the groove on the positioning steel ball or shift fork shaft is worn, it can also cause the transmission to shift.
(3) Improper adjustment of the shifting device. The gearbox of this excavator adopts a mechanical manual shifting method. If the gear lever, vertical axis, horizontal axis, and vertical fixing screws are loose, it can also cause the gearbox to "jump".
(4) Sudden changes in external loads can also cause the gearbox to shift due to the working nature of the excavator and the design of the machine itself. When the road surface is uneven, the machine is driving downhill, or the driving route is improper, causing a sudden change in external load, this sudden change in load will act on the gear meshing gear of the transmission through the wheels and transmission shaft, causing the gear meshing gear to detach due to axial thrust, causing the transmission to "jump gears".
(5) Improper operation of excavators on slopes (especially downhill driving) can also cause the transmission to "shift" if operated improperly.
