Gear-shifting pin shaft for heavy truck

A gear-shifting pin shaft for a heavy truck comprises a fixing shaft I and a fixing shaft II, wherein the fixing shaft I and the fixing shaft II are connected coaxially, the external diameter of the fixing shaft I is matched with the size of the installation hole of a support, and the external diameter of the fixing shaft II is matched with the size of an inner ring of a manipulator knuckle bearing. External threads are arranged at the outer side end of the fixing shaft I, and a limiting step I with the diameter larger than the external diameter of the fixing shaft I is arranged at the inner side end of the fixing shaft I. A clamping groove used for installing a shaft check ring is formed in the outer side end of the fixing shaft II in the circumferential direction, and a limiting step II with the diameter larger than the external diameter of the fixing shaft II is arranged at the inner side end of the fixing shaft II. The fixing shaft I is fixed into the installation hole of the support in a screwed mode through the external threads, and the limiting step I has a limiting effect; the knuckle bearing is installed on the fixing shaft II in a transition fit mode and clamped into the clamping groove to be fixed through the shaft check ring, and the limiting step II has a limiting effect on the other end. Because the limiting step I and the limiting step II can guarantee the gap between the installation support and a manipulation system, the gear-shifting stroke is guaranteed.