Full-time four-wheel drive transmission of commercial vehicle

The utility model discloses a commercial vehicle full-time four-wheel-drive transmission which comprises a transmission shell, an input shaft and a second shaft, and a first-gear gear set, a second-gear gear set, a third-gear gear set, a fourth-gear gear set, a fifth-gear gear set, a reverse-gear gear set and synchronizers used in cooperation with all the gear sets are meshed between the input shaft and the second shaft. A front output shaft and a rear output shaft are further rotationally installed in the transmission shell in a penetrating mode, a four-wheel-drive gear set is meshed among the second shaft, the front output shaft and the rear output shaft, the four-wheel-drive gear set is in transmission connection with a differential mechanism, and the front output shaft and the rear output shaft are in transmission connection with the differential mechanism. The four-wheel drive gear set is matched with the differential mechanism to achieve four-wheel drive of a commercial vehicle, so that the transmission