Automatic Transmission Rebuilders Association, also known as ATRA, is an international trade association. It offers a range of diagnostic and repair services for manual transmissions, clutches, differentials, driveshafts, drive axles and transfer cases. The company provides online Rebuilder and Diagnostician certifications for its members. Automatic Transmission Rebuilders Association is located in Oxnard, Calif. It conducts various trade shows and maintains a book store that stocks books on various topics. The company offers rebuilder, technical, supplier and international membership options.