The Komatsu PC128US-2 is a robust and reliable excavator, part of the US-2 Series, designed for demanding construction and earthmoving applications. Featuring a powerful Komatsu S46D102E diesel engine with a displacement of 3.41 L and a direct injection fuel system, this machine delivers efficient performance. Its hydrostatic drive system with variable speed control ensures precise maneuverability. With an operating weight of 13500 kg and dimensions including a length of 7380 mm with arm and bucket, a width of 2500 mm, and a cab height of 2630 mm, the PC128US-2 is engineered for productivity and stability in various work environments. This comprehensive manual provides essential information for the operation, maintenance, and repair of the Komatsu PC128US-2 and PC138U models. It includes detailed shop manual procedures and operation and maintenance guidelines, covering critical aspects such as engine oil specifications and capacity, hydraulic oil capacity, coolant capacity, and service intervals for engine oil and hydraulic oil filters. This resource is invaluable for owners, operators, and technicians seeking to ensure the optimal performance, longevity, and safety of their equipment.