Chevrolet Silverado / GMC Sierra. Service manual — part 2834

10

Transfer Case Two/Four Wheel Drive Synchronizer Sleeve

11

Transfer Case Two/Four Wheel Drive Shift Fork Inserts

12

Transfer Case Shift Fork Spring

13

Transfer Case Two/Four Wheel Drive Shift Fork Assembly

14

Transfer Case High/Low Shift Fork

15

Transfer Case High/Low Shift Fork Inserts

16

Transfer Case Control Actuator Shaft

17

Transfer Case Shift Detent Lever Assembly

18

Transfer Case Rear Output Shaft

19

Transfer Case Two/Four Wheel Drive Synchronizer Inserts

20

Transfer Case Two/Four Wheel Drive Synchronizer Hub

21

Transfer Case Two/Four Wheel Drive Synchronizer Assembly

22

Transfer Case Two/Four Wheel Drive Synchronizer Blocking Ring -
Outer

23

Transfer Case Two/Four Wheel Drive Synchronizer Blocking Ring -
Inner

24

Transfer Case Front Output Shaft Drive Chain Assembly

25

Transfer Case Front Output Shaft Drive Sprocket

26

Transfer Case Front Output Shaft Drive Sprocket Bearing Assembly

27

Transfer Case Front Output Shaft Drive Sprocket Spacer - Rear

28

Transfer Case Front Output Shaft Drive Sprocket Retaining Ring

29

Transfer Case Oil Pump Assembly

30

Transfer Case Rear Output Shaft Speed Reluctor Wheel

31

Transfer Case Rear Output Shaft Rear Bearing Retaining Ring

32

Transfer Case Rear Output Shaft Rear Bearing Assembly

33

Transfer Case Rear Output Shaft Rear Bearing Retaining Ring

34

Transfer Case Oil Pump Suction Pipe

35

Transfer Case Oil Pump Suction Pipe Seal

36

Transfer Case Front Output Shaft Driven Sprocket Spacer Spring

37

Transfer Case Front Output Shaft Driven Sprocket Spacer

38

Transfer Case Front Output Shaft Driven Sprocket

39

Transfer Case Front Output Shaft Hole Plug

40

Transfer Case Front Output Shaft

41

Transfer Case Front Output Shaft Front Bearing Assembly

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Transfer Case - MP 1222/1225/1226-NQG - Cab & Chassis Sierra, Cab & Chassis Silverado,

Sierra & Silverado

DIAGNOSTIC INFORMATION AND PROCEDURES

DIAGNOSTIC CODE INDEX

DIAGNOSTIC CODE INDEX

DIAGNOSTIC STARTING POINT - TRANSFER CASE

Begin the system diagnosis with the Diagnostic System Check - Vehicle . The Diagnostic
System Check will provide the following information:

The identification of the control module or modules that command the system.

The ability of the control module or modules to communicate through the serial data circuit.

The identification of any stored diagnostic trouble codes (DTCs) and the status of the codes.

The use of the Diagnostic System Check - Vehicle will identify the correct procedure for
diagnosing the system and where the procedure is located.

DTC P2160 OR P2161

Diagnostic Instructions

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

Review Strategy Based Diagnosis for an overview of the diagnostic approach.

Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC P2160

Vehicle Speed Sensor (VSS) 2 Circuit Low Voltage

DTC P2161

Vehicle Speed Sensor (VSS) 2 Circuit Intermittent

Diagnostic Fault Information

DTC

Description

DTC P2160 or P2161

P2160: Vehicle Speed Sensor (VSS) 2 Circuit Low Voltage

P2161: Vehicle Speed Sensor (VSS) 2 Circuit Intermittent

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Transfer Case - MP 1222/1225/1226-NQG - Cab & Chassis Sierra, Cab & Chassis Silverado,

Sierra & Silverado

Circuit/System Description

The vehicle speed sensor (VSS) provides vehicle speed information to the engine control module
(ECM). The VSS is a permanent magnet generator. The sensor is mounted in the transfer case
facing the rear internal gear which is splined to the output shaft assembly. As the output shaft and
internal gear rotate, the toothed rotor of the internal gear produces AC voltage as the rotor teeth
pass through the magnetic field of the sensor. The AC voltage level and the number of pulses
increase as the speed of the vehicle increases. The ECM converts the voltage to vehicle speed.
The ECM uses the output shaft speed signal to determine shift timing and torque converter clutch
(TCC) scheduling, as well as transfer case range.

Conditions for Running the DTC

P2160

No input speed sensor (ISS) DTCs P0716 or P0717.

No OSS DTCs P0722 or P0723.

No transmission fluid pressure (TFP) DTCs P1810, P1815, P1816, or P1818.

The transmission is not in PARK or NEUTRAL.

Transmission fluid temperature (TFT) is between -40° to +150°C (-40° to +302°F).

The throttle position is 8 percent or greater.

The engine torque is greater than 50 N.m (37 lb ft).

The input speed is greater than 1,500 RPM.

The TCC slip speed is at least -20 RPM.

P2161

No 1-2 Shift Solenoid Electrical DTC P0974.

No ISS DTCs P0716 or P0717.

The transmission is not in PARK or NEUTRAL.

The transmission output speed is greater than 1,400 RPM for 2 seconds or greater.

Circuit

Short to

Ground

Open/High

Resistance

Short to

Voltage

Signal

Performance

VSS Supply Voltage

P2160,

P2161

P2160, P2161

P2160,

P2161

P2161

VSS Signal

P2160,

P2161

P2160, P2161

P2160,

P2161

P2161

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Transfer Case - MP 1222/1225/1226-NQG - Cab & Chassis Sierra, Cab & Chassis Silverado,

Sierra & Silverado

One of the following conditions exist:

The transmission input shaft speed has changed less than 500 RPM for at least 2
seconds.

The transmission output shaft speed has not increased at least 500 RPM for at least 2
seconds.

Conditions for Setting the DTC

P2160

The transfer case output shaft speed is 50 RPM or less for 4.5 seconds.

P2161

The transfer case output shaft speed drops 1,200 RPM or greater for at least 3.25 seconds.

Action Taken When the DTC Sets

DTCs P2160 and P2161 are Type B DTCs.

The TCM commands maximum line pressure.

The TCM freezes transmission adaptive functions.

The TCM calculates vehicle speed from the automatic transmission input shaft speed sensor
and commanded gear.

Conditions for Clearing the DTC

DTCs P2160 and P2161 are Type B DTCs.

Diagnostic Aids

Inspect the rear internal gear teeth for damage.

Visually inspect the VSS for cracks or damage.

Ensure the VSS is properly torqued to the transfer case housing.

This diagnostic relates to the VSS located in the transfer case and not the OSS located
within the transmission.

Reference Information

Schematic Reference

Transfer Case Control Schematics

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Transfer Case - MP 1222/1225/1226-NQG - Cab & Chassis Sierra, Cab & Chassis Silverado,

Sierra & Silverado