A turbine engine assembly comprising: a low spool including a low spool accessory drive gear driven by a low rotor shaft ; a high spool including a high spool accessory drive gear driven by a high rotor shaft , the high rotor shaft concentric around a portion of the low rotor shaft ; and a differential gear assembly adapted to offtake power from rotation of one or both of the low spool and the high spool to drive one or more accessory loads , the differential gear assembly comprising: a first idler gear and a second idler gear , each including a plurality of teeth meshed with the low spool accessory drive gear and the high spool accessory drive gear , and a bearing surface ; and a differential bull gear including a plurality of teeth and a corresponding at least one bearing surface engaging with the bearing surface of each of the first and second idler gears , the plurality of teeth adapted to mesh with an accessory drive system to transfer the power offtake and drive the one or more accessory loads , characterized in that the low spool accessory drive gear comprises a ring gear assembly including a ring gear supported to the low rotor shaft by a first plurality of bearings and a pinion gear meshed with the ring gear , and in that the ring gear assembly is radially inward of the one or more idler gears. a low spool including a low spool accessory drive gear driven by a low rotor shaft ; a high spool including a high spool accessory drive gear driven by a high rotor shaft , the high rotor shaft concentric around a portion of the low rotor shaft ; and a differential gear assembly adapted to offtake power from rotation of one or both of the low spool and the high spool to drive one or more accessory loads , the differential gear assembly comprising: a first idler gear and a second idler gear , each including a plurality of teeth meshed with the low spool accessory drive gear and the high spool accessory drive gear , and a bearing surface ; and a differential bull gear including a plurality of teeth and a corresponding at least one bearing surface engaging with the bearing surface of each of the first and second idler gears , the plurality of teeth adapted to mesh with an accessory drive system to transfer the power offtake and drive the one or more accessory loads , characterized in that the low spool accessory drive gear comprises a ring gear assembly including a ring gear supported to the low rotor shaft by a first plurality of bearings and a pinion gear meshed with the ring gear , and in that the ring gear assembly is radially inward of the one or more idler gears. a first idler gear and a second idler gear , each including a plurality of teeth meshed with the low spool accessory drive gear and the high spool accessory drive gear , and a bearing surface ; and a differential bull gear including a plurality of teeth and a corresponding at least one bearing surface engaging with the bearing surface of each of the first and second idler gears , the plurality of teeth adapted to mesh with an accessory drive system to transfer the power offtake and drive the one or more accessory loads , characterized in that the low spool accessory drive gear comprises a ring gear assembly including a ring gear supported to the low rotor shaft by a first plurality of bearings and a pinion gear meshed with the ring gear , and in that the ring gear assembly is radially inward of the one or more idler gears. <EOS>