MULTI-SPEED HYBRID TRANSMISSION AND TRANSMISSION OPERATING METHOD

A hybrid transmission system with a multi-speed gearbox. The multi-speed gearbox is configured to rotationally couple a prime mover and an electric machine to different gear ratios during a hybrid drive mode. The multi-speed gearbox includes an electric drive interface gear positioned coaxial to a first primary shaft and a second primary shaft and idly mounted, free to spin, to the second primary shaft and an output shaft that includes an output shaft gear which is fixedly coupled thereto meshes with a gear on a secondary shaft.