Chevrolet Silverado / GMC Sierra. Service manual — part 2953

Fig. 57: View Of Transfer Case Assembly, Input Shaft Seal & Front Output Shaft Seal
Courtesy of GENERAL MOTORS CORP.

Input Shaft Seal and Front Output Shaft Seal Installation

DESCRIPTION AND OPERATION

TRANSFER CASE IDENTIFICATION

Callout

Component Name

1

Transfer Case Input Shaft Seal
Tip: Ensure the bore of the front case half is free
of dirt, oil, and cleaning solvent.
Special Tools:
J 42738 Seal Installer

2

Transfer Case Front Output Shaft Seal

Special Tools

J 8092 Driver Handle

J 43484 Front Output Shaft Seal Installer

3

Transfer Case Assembly
Tip: Remove from J 3289-20 and remove the J
45759 from the transfer case.

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Transfer Case - MP 3023/3024-NQH - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &

Silverado

Fig. 58: Transfer Case I.D. Label
Courtesy of GENERAL MOTORS CORP.

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Transfer Case - MP 3023/3024-NQH - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &

Silverado

Fig. 59: Magna Transfer Case Bar Code Label
Courtesy of GENERAL MOTORS CORP.

TRANSFER CASE DESCRIPTION AND OPERATION

The Magna Powertrain (MP) model 3023/3024 RPO NQH transfer case is a 2 speed automatic,
active transfer case (ATC). The MP 3023/3024 ATC provides 5 modes, Auto 4WD, 4HI, 4LO,
2HI and NEUTRAL. The Auto 4WD position allows the capability of an active transfer case,
which provides the benefits of on-demand torque biasing wet clutch and easy vehicle tuning
through software calibrations. The software calibrations allow more features such as flexible
adapt ready position and clutch preload torque levels. The technology allows for vehicle speed
dependent clutch torque levels to enhance the performance of the system. For example, the system
is calibrated to provide 0-6.78 N.m (0-5 lb ft) of clutch torque during low speed, low engine
torque operation, and predetermined higher torque for 40 km/h (25 mph) and greater. This
prevents crow-hop and binding at low speeds and provides higher torque biases at higher vehicle
speeds, in order to enhance stability.

Transfer Case Shift Control Switch

Callout

Component Name

1

Component Identifier

2

GM Broadcast Code

3

Supplier Code

4

Production Year

5

Julian Date of the Year

6

Assembly Line Number

7

Sequential Number

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Transfer Case - MP 3023/3024-NQH - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &

Silverado

Fig. 60: Transfer Case Shift Control Switch
Courtesy of GENERAL MOTORS CORP.

The MP 3023/3024 ATC transfer case features a 4 mode shift control switch located on the
instrument panel. When the ignition key is in the RUN position, the transfer case shift control
module monitors the transfer case shift control switch to determine if the driver desires a new
mode/range position. At a single press of the transfer case shift control switch, the lamp of the
new desired position will begin flashing to inform the driver that the transfer case shift control
module has received the request for a new mode/range position. The lamp continues to flash until
all shifting criteria has been met and the new mode/range position has been reached, or has been
engaged. Once the new mode/range position is fully active, the switch indicator lamp for the new
position will remain ON constantly.

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Transfer Case - MP 3023/3024-NQH - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &

Silverado