(1) The internal gear teeth of the auxiliary speed sliding gear are worn out, the sliding gear is thrown off under heavy load, and the gear is automatically cut and jumped. Need to replace the auxiliary speed sliding gear in time. (2) Auxiliary shift fork wear or deformation, so that the sliding gear produces axial shift jump. Replace the worn out fork in time. (3) The shift lever is not pushed to the end, causing the slide gear to throw off the jump gear. Need to push the gear lever to the end. (4) The locking groove of the locking steel ball and the fork shaft is severely worn so that the spring force of the locking spring is weakened and the gear jumps. The lock spring must be repaired or replaced.
