This document provides a service manual for D125C Crawler Dozers with Power Angle Tilt blades in both Long Track and Wide Track configurations that meet Tier 2 emissions standards. It contains sections covering the engine, hydrostatic drive, brakes and controls, hydraulic systems, tracks and suspensions, cab climate control, electrical systems, dozer blade and arm, and platform, cab, bodywork and decals. Safety information is also provided to ensure safe operation and service of the equipment.