Chevrolet Silverado / GMC Sierra. Service manual — part 2831

Fig. 91: Power Flow
Courtesy of GENERAL MOTORS CORP.

When the BW 4485 is operating in the AWD mode, the power flows from the transmission to the
transfer case input shaft (1). The input shaft (1) delivers the power to the planetary differential
(4). The case of the planetary differential (4) is splined to the input shaft (1). The planetary
differential (4) splits the torque 40 percent through the front differential pinion gears (3) to the
front sun gear (8). The front sun gear (8) is engaged with the drive sprocket (2), which drives the
chain (9) to the front output shaft (10), and power is delivered to the front propeller shaft. 60
percent of the torque to the rear output shaft (6) goes through the rear differential pinion gears (7)
and rear sun gear (5), which is connected to the rear output shaft (6) and to the rear propeller
shaft.

SPECIAL TOOLS AND EQUIPMENT

SPECIAL TOOLS

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Transfer Case - BW 4485-NR3 - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &

Silverado

Illustration

Tool Number/Description

J 2619-01

Slide Hammer

J 3289-20

Holding Fixture

J 8092

Driver Handle

J 22912-01

Rear Pinion and Axle Bearing Remover

J 23907

Slide Hammer with Bearing Adapter

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Transfer Case - BW 4485-NR3 - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &

Silverado

J 26941

Bushing and Bearing Remover - 3-4 inch

J 36825

Output Shaft Oil Seal Remover (4WD

Models Only)

J 36850

Transjel Lubricant

J 42176

Universal Driver Handle - Non-Threaded

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Transfer Case - BW 4485-NR3 - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &

Silverado

J 42738

Seal Installer

J 43484

Front Output Shaft Seal Installer

J 45124

Removal Bridge

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Transfer Case - BW 4485-NR3 - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &

Silverado