the drive power is transmitted from the front part of the power takeoff shaft 39 to the front propeller shaft 26 for the front wheels 1 through the spline coupling 28 on the other hand the drive power is transmitted from the rear part of the power takeoff shaft 39 to the rear propeller shaft 36 for the rear wheels 2 through a constant velocity universal coupling 40 the drive power which is transmitted to the front propeller shaft 26 is reduced in rotational speed inside the differential gear 20 the drive power is then transmitted to both of the constant velocity universal joints 22 to both of the front wheel drive shafts 23 to both of the constant velocity universal joints 24 and to both of the front wheels 1 referring to fig3 the drive power which is transmitted to the rear propeller shaft 36 in a posture of inclination as explained above is transmitted to the input shaft 35 of the final reduction gear 30 through the spline coupling then the drive power is changed in direction by the small bevel gear 37 and the large bevel gear 38 while the drive power is reduced in rotational speed the drive power is transmitted to both of the output shafts 31 through the hollow shaft 61 and then the drive power is transmitted to both of the drive shafts 33 through both of the constant velocity universal couplings 32 in fig4 the lubricant contained in the oil sump 79 on the bottom part of the wet multiple disk wet braking device 50 is forced to be flowed upwards in the.