A carrier shaft set includes an input carrier shaft portion and a carrier shaft portion. The input carrier shaft portion has an input carrier shaft portion axis defined between a planetary gear set end and an input shaft end having an outer surface. The input carrier shaft portion includes a wedge-shaped member having an outer edge. A ratio of a length defined between the input carrier shaft portion axis and the outer edge to the outer surface is between 1.23 and 1.30. The carrier shaft portion has a carrier shaft portion axis defined between a planetary gear set end and a shaft end. The carrier shaft portion includes a shaft portion having an outer surface and a wedge-shaped member having an outer edge. A ratio of a length defined between the carrier shaft portion axis and the outer edge to the shaft portion outer surface is between 1.23 and 1.30.
