This manual covers the Allison 3000 and 4000 Series 4th Generation automatic transmissions, designed for robust performance in commercial vehicles, buses, and RVs. These transmissions are engineered with electronic control systems and feature a lock-up clutch torque converter for enhanced efficiency. The 3000 and 4000 Series are both 6-speed automatic transmissions, known for their reliability and suitability for demanding applications requiring dependable power delivery and smooth operation. The purpose of this English-language service repair workshop manual is to provide comprehensive guidance for maintaining and repairing your Allison 3000/4000 Series transmission. It details essential procedures, including fluid specifications and capacity guidelines for both series, as well as diagnostic information compatible with OBD-II systems. This manual serves as a vital resource for owners, mechanics, and technicians, enabling them to perform routine maintenance, troubleshoot issues, and ensure the optimal performance and longevity of the transmission.