John Deere Gator 825i Automatic Engaging Front Differential Hub Assembly

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The 2017 John Deere Gator 825i's front differential features electrically operated automatic engaging hubs for seamless power transfer between rear wheel drive, one front and rear wheel drive, or full four-wheel drive depending on traction conditions. The automatic hub differential system is controlled by the mechanical rotational speed of the wheels, with a reference image provided for guidance. John Deere's Electro Mechanical Front Wheel Drive (EMFWD) engages when the electronic four-wheel-drive switch is turned on and rear wheel speed exceeds front wheel speed, supplying power to both sets of wheels. In 4WD operation, the system drives only the rear wheels until they slip, then engages the EMFWD for dual power supply. When both sets of wheels rotate at equal speeds, the system disengages, reverting back to rear-wheel drive. This process is activated when the transmission is in forward or reverse gear and the 4WD switch is on, with voltage applied to the solenoid to move the plunger, block rotating tabs and drag washer, engaging the roller cage and output hubs for friction lock, preventing slippage.