Due to the ongoing shortage of rural labor and the aging farming population, the farm size per farmer has increased, demanding durable and reliable agricultural equipment. In response to this demand, an accelerated life test (ALT) technique for the tractor axle was developed based on measured load data during actual field operations. Robust axle systems were required for high torque at low speeds of tractors, particularly during high-load operations such as plow tillage. In this study, axle torques and rotational speeds were measured for both the front and rear axles using telemetry torque sensors. The measured data were segmented into torque ranges, and a Load Duration Distribution (LDD) was analyzed. Equivalent torque was calculated by applying the Palmgren–Miner linear damage rule, and a fatigue damage exponent was assumed as 8.738. The equivalent torque was obtained as 6,310.99 Nm. The applied torque was approximately 8,170.08 Nm, which is 1.2 times the rated torque. The acceleration factor was calculated as 9.545, which reduced the durability test time from 3,000 to 314.3 hours. The proposed technique provides a quantifiable and efficient method for evaluating axle fatigue life under actual working conditions. It was expected that this technique could be adapted to other equipment in future research, contributing to enhanced drivetrain reliability, shortened product development cycles, and reduced maintenance and production costs of the agricultural machinery.