"Load-bearing" is usually an architectural term and confusing to use in this application. Power is transmitted through the Leaf motor male splined output shaft, mostly as a twisting force, to the bearing supported female splined input shaft of the gear reducer/differential unit. The motor output shaft and its support bearing may be too small to handle the side loads imposed by a sprocket or gear attached to the motor output shaft for a belt, chain, or gear drive.
What kind of drive and/or application were you thinking of?