Powerflow

In all drive range positions input torque is transmitted to the transfer case gear train through the transfer case input gear.
In 2Hi range, torque flows from the input gear to the range shift hub and mainshaft. Torque flow continues through the slip/fixed yoke which is splined to the mainshaft, and finally to the rear propeller shaft and axle. In 2HI range, the mode synchronizer remains in the neutral position. As a result, torque is not transferred to the driven sprocket.

In 4HI range, input torque from the input gear is transmitted to the mainshaft in exactly the same fashion as in 2HI range. However, in 4HI position, the mode synchronizer sleeve is shifted into engagement with the clutch hub teeth on the mainshaft. This locks the drive sprocket to the mainshaft through the synchronizer assembly. Torque is transmitted through the drive sprocket by the connecting drive chain. Since the front output shaft is splined to the driven sprocket, torque flows through the front output shaft to the front propeller shaft and axle resulting in high range four-wheel drive.

In 4LO range, the path of torque through the transfer case is exactly the same as in 4HI range but with one major difference. In 4LO range the range hub is shifted into engagement with the planetary carrier. This causes the input gear to rotate the planetary pinions inside the fixed annulus gear, causing the planetary carrier, range shift hub, and mainshaft to rotate at a gear reduction of 2.69:1.