A gearbox assembly for power take off from an electric motor of an electric power assisted steering apparatus comprising a gearbox housing which houses a worm shaft and a gear wheel, is disclosed. The worm shaft incorporates one or more external helical worm teeth. A main bearing assembly supports the worm shaft at an end closest to the motor. A tail bearing assembly supports the worm shaft at an end furthest from the motor, in which at least the tail bearing assembly is free to move relative to the housing through a limited range of motion that enables the worm shaft to move radially away from the axis of the wheel gear. The gearbox assembly further comprises a flexible coupler which connects the worm shaft at the main bearing end to a power take off from the motor so as to transfer torque from the motor to the worm shaft. The flexible coupler comprises a first hub part providing a connection to the worm shaft, a second hub part providing a connection to the power take off from the motor, and a flexible membrane that connects the first hub part to the second hub part. The flexible membrane provides a primary path for the transfer of torque from the first hub part to the second hub part.