2WD Mode Power Flow

WARNING: This page is about a different car, the 2009 GMC Sierra, 2009 GMC Cab & Chassis Sierra, 2009 Chevrolet Silverado, and 2009 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

Fig 1: Identifying 2WD Mode Power Flow Components

Courtesy of GENERAL MOTORS CORP.

Callout	Component Name
1	Input Shaft
2	Two/Four Shift Fork
3	Drive Chain
4	Rear Output Shaft
5	Control Actuator Shaft
6	Front Output Shaft
7	Drive Actuator Cam

Fig 2: View Of 2WD Mode Power Flow

Courtesy of GENERAL MOTORS CORP.

The transfer case is shifted by an encoder motor (9) on the control actuator shaft. The control actuator shaft rotates the 2/4 wheel drive actuator cam (10) and moves the high/low range shift fork (12) or the 2/4 wheel drive mode shift fork (8). Depending on the selected mode or range, the shift forks move either the high/low clutch (4) for the high/low range planetary assembly (3) or the synchronizer sleeve (6) for the 2/4 wheel drive mode. In 2WD mode, the engine power from the transmission (1) is delivered to the input shaft (2). The engagement teeth on the inside of the input shaft (2) are engaged to the outer teeth on the high/low clutch (4). The high/low clutch (4) is slip splined to rear output shaft (5). The engine power flows from the high/low clutch (4) to the rear output shaft (5) and delivered to rear propeller shaft (7).