Mechanical Operation
In the 2WD mode, torque from the engine is transferred through the transmission to the transfer case, which in turn drives the output shaft that drives the rear axle.
The 2WD to 4WD HIGH shift is accomplished when the 2WD to 4WD HIGH shift fork moves the mode sleeve to engage the drive sprocket to the rear output shaft. The drive sprocket turns the chain which turns the front output shaft driven sprocket on the front output shaft and the front driveshaft.
The 4WD HIGH to 4WD LOW shift is accomplished when the 4WD HIGH to 4WD LOW shift fork moves the range sleeve to engage the planet carrier to the main shaft. Torque for the input shaft is then transmitted through the sun gear, which then turns the planets. The planets, which are now engaged to the output shaft, provide a gear reduction.