2HI to 4HI Power Flow

WARNING: This page is about a different car, the 2007 Isuzu i-370, 2007 GMC Canyon, and 2007 Chevrolet Colorado. However, it is still accessible from the selected car via links, so may be relevant.

Fig 1: 2HI To 4HI Power Flow

Courtesy of GENERAL MOTORS CORP.

During operation in 2HI mode, the input shaft (105) delivers the engine power from the transmission. The high/low range sleeve (230) connects the input shaft (105), to the rear output shaft (124). The high/low range sleeve (230) outer teeth engage with the input shaft (105) inner teeth, which are the high-speed teeth. The high/low range sleeve (230) is slip splined to the rear output shaft (124). The rear output shaft (124) delivers the engine power to the rear propeller shaft.

When commanding the transfer case to 4HI mode, the actuator assembly (200) rotates the control actuator cam (262). The control actuator cam (262) moves the 2/4 wheel drive shift fork (243) rearward. The 2/4 wheel drive shift fork (243) moves the synchronizer sleeve (224) of the 2/4 wheel drive synchronizer (220), to the blocking rings (223). The blocking rings (223) brake the drive sprocket (123) to match the revolutions of the rear output shaft (124). Matching the revolutions, the synchronizer sleeve (224) engages the synchronizer hub (227) to synchronizer blocking rings (223), which are connected to the drive sprocket (123). The synchronizer hub (227) is pressed fit on the rear output shaft (124). The engine power now flows through the synchronizer assembly (220) to the drive sprocket (123). A chain (120) connects the drive sprocket to the driven sprocket on the front output shaft (127), delivering the engine power now to both the front propeller shaft and the rear propeller shaft.