4HI Mode Power Flow
When the BW 4493, shown, or the BW 4494, shown in inset, is in 4HI mode, the engine power flows from the transmission to the input shaft (1). The input shaft (1) is connected to the mainshaft (3) by the high/low range sleeve (2). The high/low range sleeve (2) outer teeth are engaged with the input shaft (1) high-speed teeth. The range collar is slip splined to the mainshaft (3). The mainshaft (3) delivers the power flow to the planetary differential (6), which splits the torque 40 percent through the front differential pinion gears (5) to the front output sun gear (10). The torque to the front axle then goes through the drive sprocket (4), via the chain (11) to the front output shaft (12) and to the front axle. The differential planetary splits the torque 60 percent to differential rear pinion gears (9) and rear output sun gear (7). The rear output sun gear is connected to the rear output shaft (8) and the torque flows to the rear axle. In the 4HI mode, if traction is lost to 1 axle and the tires spin, the traction assist system (TAS) applies braking to the spinning tires and the engine power is delivered to the other tires.