The present disclosure is directed to a gearbox repair apparatus for repairing a bore hole of a gearbox torque arm. In certain embodiments, the apparatus includes a mounting structure configured to mount to the torque arm. The mounting structure includes a through hole that aligns with the bore hole of the torque arm when mounted thereto. As such, when mounted to the torque arm, the mounting structure is configured to locate a boring bar at a center of the bore hole such that the boring bar is perpendicular to a face of the torque arm. Further, the mounting structure is configured to receive the boring bar through the aligned through hole and bore hole such that, when inserted therethrough, the boring bar is configured to machine and thus repair the bore hole.