This Service Repair Manual covers the Allison 4800 EVS transmission, a component of the 4000 Product Family featuring 4th Generation Controls. While specific production years are not detailed, this manual focuses on the engineering and operational aspects of this transmission, known for its reliability and integration into various vehicle applications. Notable optional features include a Power Takeoff (PTO) and an Output Retarder, enhancing its versatility for demanding tasks. This comprehensive English-language manual is designed to provide essential information for owners, mechanics, and technicians. It details critical maintenance procedures, including preventive maintenance, general overhaul, and customer service aspects. The manual also offers in-depth troubleshooting guidance, technical specifications such as wear limits and spring data, and detailed explanations of major components. Extensive visual aids, including line drawings, cross-sectional views, and foldout illustrations of the hydraulic schematic, are provided to support step-by-step repair instructions, enabling efficient and cost-effective maintenance.