The Massey Ferguson 3670, 3680, and 3690 tractors represent robust, heavy-duty machines designed for demanding agricultural applications. These tractors, likely produced during the 1980s and early 1990s, are characterized by their powerful Perkins diesel engines, advanced hydraulic systems, and versatile power take-off options, positioning them as strong competitors in their class. Their engineering emphasizes durability and performance, making them reliable workhorses for farmers and agricultural contractors. This comprehensive service repair manual provides detailed guidance for maintaining and repairing the Massey Ferguson 3670, 3680, and 3690 tractors. It covers all major systems, including the engine, transmission, hydraulics, electrical, braking, and steering systems, offering step-by-step procedures for diagnostics, repair, overhaul, and adjustment. Essential technical specifications, torque values, and troubleshooting charts are included, empowering owners, mechanics, and technicians to ensure the optimal performance and longevity of these agricultural machines.