A geartrain for a powertrain system is disposed to transfer mechanical power between an internal combustion engine, an electric machine and a driveline. The geartrain includes a flywheel, a torque converter, an off-axis mechanical connection and a transmission gearbox. The off-axis mechanical connection includes a first element rotatably coupled to a second element. The flywheel is coupled to a crankshaft of the internal combustion engine. The torque converter includes a pump, a turbine and a pump hub, and the transmission gearbox includes an input member. The pump of the torque converter is coupled to the flywheel, and the pump hub is coupled to the first element of the off-axis mechanical connection. The second element of the off-axis mechanical connection is coupled to a rotor of the electric machine, and the turbine of the torque converter is coupled to the input member of the transmission gearbox.