This manual covers the Komatsu WA1200-3 Series wheel loader, a robust machine designed for heavy-duty applications. Featuring a powerful Cummins QSX15 diesel engine with a displacement of 15.0 L and a net power output of 373 kW (500 hp) at 1800 rpm, this loader is engineered for exceptional performance and reliability. Its Komatsu Advanced Transmission, electronically controlled with 4 forward and 4 reverse gears, ensures efficient power delivery. With an impressive operating weight of 99,500 kg (219,365 lbs) and a bucket capacity of 10.0 m³ (13.1 yd³), the WA1200-3 is built to handle demanding tasks in mining, quarrying, and large-scale construction. The Full Service Repair Manual provides comprehensive guidance for the maintenance, repair, and technical understanding of the Komatsu WA1200-3 Series. It details critical information such as fluid capacities for engine oil, transmission, hydraulics, fuel, and coolant, alongside specifications for key components like the engine, transmission, and chassis systems. This manual is an essential resource for owners, operators, and service technicians, offering detailed procedures and technical data necessary to ensure the optimal performance, longevity, and safe operation of the equipment.