Propshafts and propshaft assemblies for transferring torque in motor vehicles, and methods for fabricating such propshafts are provided. In one example, a propshaft comprises a fiber reinforced composite tube having a channel. The propshaft comprises a fiber reinforced composite tube and a splined female insert. The fiber reinforced composite tube has a channel and comprises a composite wall that is disposed around the channel. The splined female insert comprises a buried wall portion that is disposed in the channel operatively coupled to the composite wall. The buried wall portion has an inner surface and a plurality of internal splines formed along the inner surface.