The Yanmar YM155D is a compact utility tractor renowned for its robust diesel engine and versatile performance, designed to meet the demands of small to medium-sized farms, landscaping projects, and general property maintenance. Built by Yanmar, a Japanese manufacturer with a strong heritage in agricultural machinery and diesel engines, the YM155D exemplifies the brand's commitment to durability and reliability. This model typically features a 3-cylinder diesel engine, a manual transmission with multiple gear configurations, and a rear Power Take-Off (PTO) for various implement attachments, making it a capable and efficient workhorse for a wide range of tasks. This comprehensive factory service repair manual provides essential, in-depth information for the Yanmar YM155D. It covers all critical systems, including detailed procedures for engine mechanical work, fuel, cooling, lubrication, exhaust, transmission and drivetrain, hydraulics, electrical systems, brakes, steering, chassis, and body components. The manual also outlines routine and preventive maintenance schedules, troubleshooting diagnostics for common issues, and specific repair and rebuild instructions for major systems like the engine and transmission. Its purpose is to empower owners, technicians, and repair shops with the knowledge required to maintain, service, and repair the YM155D effectively, thereby reducing reliance on external services and extending the equipment's operational lifespan.