Auxiliary tool for gas tightness testing of transmission

The invention discloses an auxiliary tool for gas tightness testing of a transmission. The auxiliary tool for the gas tightness testing of the transmission is arranged at ports of a differential mechanism of the transmission and comprises an upper sealing element, a lower sealing element, a supporting column connecting the upper and the lower sealing elements, the supporting column is C-shaped, the upper sealing element and the lower element are respectively inosculated with the ports of the differential mechanism, and the upper sealing element is movable and can move up and down along the axis of the ports of the differential mechanism. The upper port and the lower port of the differential mechanism are simultaneously sealed through the upper sealing element and the lower sealing element which are linked up and down, the auxiliary tool for the gas tightness testing of the transmission is accurate, simple and direct in sealing process, labor-saving, time-saving, simple and reliable in structure and good in tightness.