This manual covers the Komatsu D155AX-6 and Komatsu 140E-5. The Komatsu D155AX-6 is a robust crawler dozer engineered for demanding earthmoving tasks. It features a powerful Komatsu SAA6D140E-3 engine, delivering 265 HP, and a versatile Hydro-Shift transmission with three forward and three reverse gears. Its substantial operating weight of 36,430 kg and dimensions, including a length of 9720 mm with ripper, underscore its capability in heavy-duty applications. The Komatsu 140E-5 is also powered by a Komatsu engine, the SAA6D140E-5, providing an estimated 247 HP. Both models represent Komatsu's commitment to reliability and performance in construction and heavy industry. This comprehensive manual provides essential information for the maintenance and repair of the Komatsu D155AX-6 and Komatsu 140E-5. It details critical maintenance procedures, including fluid capacities for engine oil (32 L), hydraulic oil (90 L), coolant (35 L), and fuel (420 L) for the D155AX-6. Technical specifications, troubleshooting guides, and safety guidelines are included to assist owners, mechanics, and technicians. The manual aims to ensure optimal performance and longevity of these heavy-duty machines through accurate and accessible technical data.