This manual covers the Komatsu WA400-1 Wheel Loader, applicable to serial numbers 10001 and up. Engineered for reliability and performance, the WA400-1 is designed to meet demanding operational needs. Its robust construction and advanced systems ensure efficient and safe operation across various applications, making it a dependable choice for heavy-duty tasks. This comprehensive Service Repair Manual and Operation & Maintenance Manual provides detailed guidance for owners, mechanics, and technicians. It includes essential information on operation, safety, maintenance schedules, troubleshooting, and technical specifications. The manual's step-by-step procedures, diagrams, and illustrations are designed to help users maintain peak performance, ensure economical operation, and facilitate effective repairs.