The John Deere 644A Wheel Loader is a robust machine engineered for mid-sized construction and material handling tasks. It features a turbocharged 404 cu in diesel engine delivering 141 hp gross power and 131 hp net power at 2400 rpm, with peak torque of 345 lb-ft at 1600 rpm. Its variable displacement hydraulic pump provides a flow capacity of 60 gallons per minute and operates at a relief valve setting of 2250 psi, supporting efficient loader functions. The loader’s bucket capacity is 2.5 cu yds heaped and 2.1 cu yds struck, with a bucket width of 8.7 ft. It achieves a breakout force of 41,515 lbs, enabling strong digging and lifting capabilities. Key dimensions include a wheelbase of 8.7 ft, overall length with bucket on ground of 20.7 ft, and dump clearance at maximum raise of 9.3 ft, with a hinge pin max height of 11.9 ft. The operating weight is approximately 25,200 lbs. The machine supports a powershift transmission with 4 forward and 2 reverse gears, reaching a maximum forward speed of 23 mph and 9.5 mph in reverse. Tire options include 16-24 and 20.5-25 sizes, with a turning radius of 15.5 ft. Additional capacities encompass a 50-gallon fuel tank, 17.5 gallons of hydraulic fluid, and 9.8 gallons of transmission fluid. The rear axle allows 22° oscillation for terrain adaptability. Electrical systems run on 12V with a 55A alternator output. This loader delivers balanced power, hydraulics, and maneuverability for diverse construction applications.