An input shaft includes an annular main shaft extending along a longitudinal axis with an internal bore configured for fluid flow through the annular main shaft. A generator spline is included on an exterior surface of a first end of the main shaft. A gearbox spline is included on an exterior surface of a second end of the main shaft opposite the first end. At least one orifice is defined through the main shaft from the internal bore to the exterior surface of the second end of the main shaft for flow of fluid from the internal bore to the exterior surface for cooling and lubrication.