Unlike wheeled vehicles, tracked armored vehicles require a highly developed transmission technology since the transmission has to not only shift gears but also steer and brake the heavy ground weapon system precisely. Even though weapons systems including the K00 Infantry Fighting Vehicle (IFV) have recently been developed with domestic technology, it is true that many core parts in the systems are still being imported. In this paper localization process of the accumulator which is one of the most important hydraulic parts in the K00 transmission is introduced. In order to determine design variables such as operating pressure we analyzed torque characteristics of the transmission and calculated spring constant by disassembling the original accumulator. And tests such as durability, safety, etc. were conducted to assure the validation of the development. We expect that the process of reverse engineering we adopted will be helpful to localize similar hydraulic parts.