Motor-generator and prime mover gearing assembly

An example mechanical transmission assembly (56;156) receives an input (70) rotating at a first rotational speed and provides an output (72) rotating at a second rotational speed. The mechanical transmission (56; 156) selectively adjusts the second rotational speed. The input (70) is provided by a prime mover (10). The output (72) is provided to a hydraulic pump assembly (58;158) that rotatably drives a motor-generator (50;150).