Transfer boxes are integral components in four-wheel drive and all-wheel drive vehicles, mechanically distributing engine torque to multiple axles. These assemblies utilize a combination of gears and chains to enable selectable drive modes – typically 2WD, 4WD High, and 4WD Low – altering torque split and reduction ratios. Robust housings and precision-cut gears are critical for withstanding high torque loads and off-road stresses. Many modern units incorporate electronically controlled clutches for automated mode selection and variable torque distribution. Proper operation relies on synchronized input from the vehicle’s transmission, and consistent lubrication of internal components is essential for longevity.