The McCormick GM Series Tractors, encompassing models GM40, GM45, and GM50, represent a line of compact utility tractors built upon McCormick's extensive heritage in agricultural machinery. Designed for versatility, these tractors are well-suited for a variety of agricultural, horticultural, and property maintenance tasks. They feature robust build quality, user-friendly controls, and essential capabilities such as four-wheel drive, a three-point linkage, and auxiliary hydraulics, making them reliable partners for demanding work. The GM series embodies a commitment to practical engineering and operational efficiency, offering dependable performance for owners and operators. This comprehensive factory operation, maintenance, and service/repair manual provides essential information for the McCormick GM Series Tractors. It covers critical areas including tractor identification, controls, engine starting procedures, gearbox and power take-off (PTO) operation, braking systems, and the four-wheel drive system. Detailed guidance is provided on routine maintenance, lubrication, fluid checks, and adjustments, alongside procedures for hitching implements and operating auxiliary control valves. The manual is designed to assist owners, mechanics, and technicians in maintaining the tractor's longevity, ensuring safe operation, and performing necessary repairs, featuring clear explanations and detailed technical diagrams.