Automatic Transmission Service Group (ATSG) is the largest technical support service in the automatic transmission Industry. ATSG manuals are the world's foremost service guides utilized by professionals and technicians to troubleshoot and diagnose problematic areas, disassemble transmissions and reassemble accurately and efficiently. ATSG manuals cover all aspects of transmission care, overhaul and rebuild procedures. Straightforward and simple to use, ATSG manuals will assist professionals and non-professionals alike with all aspects of automotive transmission care.