Abstract: A tap changer is adapted for being mounted both internally and externally to a transformer. The tap changer includes a frame having a planar portion and a flange portion generally transverse thereto. A plurality of contacts extend from the planar portion and are adapted for engaging the associated contacts of the transformer. A pivot control assembly is connected to the flange portion and defines a pivot axis. A shaft having a female coupling system adapted for engaging the pivot control assembly is mounted thereto for rotating the shaft. A brace is provided for positioning the shaft coupling system on the pivot control system. A displaceable disk having a spring mechanism is adapted for engaging the contacts while also simultaneously maintaining engagement of the coupling systems.