Abstract: An integral coupling is provided for transmitting torque from a flexible driveplate mounted to an engine flywheel. The coupling has a base portion which is fixed to the flexible driveplate and a shaft portion which extends axially away from the base portion. The shaft portion has male splines which are shaped to be matably received in a female splined connector of a rotatable member. In particular, the female splined connector is formed in the hub of a gearbox input pinion driving a gearbox which, in turn, drives a hydraulic pump supplying hydraulic pressure to systems of a gantry crane. The integral coupling permits axial movement at the male splined end which is distally located relative to the flexible driveplate. The integral coupling provides improved performance over a conventional two-piece coupling having a male--male splined shaft which matably fit the base portion mounted to the flexible driveplate.