Chevrolet Silverado / GMC Sierra. Service manual — part 2928

TRANSFER CASE GRATING NOISE

Input shaft

Chipped teeth

Metal embedded in the root of the teeth

Refer to Front Output Shaft and Input Shaft
Cleaning and Inspection .

3. Replace the input shaft if faulty. Refer to Transfer Case

Disassemble and Transfer Case Assemble.

Thrust washers

1. Inspect for missing or damaged input shaft thrust washers.

2. Inspect the thrust washers for galling.

3. Replace the thrust washers if faulty and the mating

component if damaged. Refer to Transfer Case
Disassemble and Transfer Case Assemble.

High/low internal gear

1. Inspect the high/low internal gear teeth for the following

conditions:

Damage

Chipped teeth

Excessive wear

Metal embedded in the root of the teeth

Refer to Transfer Case Front Half Cleaning and
Inspection .

2. Replace the front case half if the high/low internal gear is

faulty. Refer to Transfer Case Disassemble and
Transfer Case Assemble.

Cause

Correction

DEFINITION: A faulty internal transfer case component that causes a grating noise in the
transfer case while in the AWD, 4HI, or 4LO mode.
Review the Symptoms - Transfer Case and perform the necessary inspections.

Broken clutch apply plate

1. Inspect for a broken clutch apply plate. Refer to

Transfer Case Disassemble and Transfer Case
Assemble.

2008 Chevrolet Silverado 1500

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

Silverado

TRANSFER CASE CLUNK IN 2HI ONLY

2. Replace the apply plate and the transfer case components

that are damaged from debris. Refer to Transfer Case
Disassemble and Transfer Case Assemble.

Faulty control actuator lever
thrust bearings

1. Inspect for faulty control actuator lever thrust bearings.

Refer to Two/Four Wheel Drive Shift Components
Cleaning and Inspection.

2. Recondition the transfer case components that are

damaged from debris. Refer to Transfer Case
Disassemble and Transfer Case Assemble.

Cause

Correction

DEFINITION: During acceleration or deceleration, a clunk is heard or felt in the transfer
case while in the 2HI mode.
Review the Symptoms - Transfer Case and perform the necessary inspections.

Incorrect fluid level or
incorrect fluid

1. Inspect the transfer case for the correct fluid level.

2. Inspect the transfer case for the correct type of fluid.

Refer to Approximate Fluid Capacities .

3. Flush the transfer case and fill with the correct fluid, if

required. Refer to Transfer Case Fluid Replacement.

Excessive clearance
between the slip yoke and
the rear output shaft

1. Inspect for the following conditions:

Worn slip yoke splines

Worn rear output shaft splines

2. Repair or replace the following components if faulty:

Replace the slip yoke, if required. Refer to One-
Piece Propeller Shaft Replacement and Two-
Piece Propeller Shaft Replacement .

Replace the rear output shaft, if required. Refer to
Transfer Case Disassemble and Transfer Case
Assemble .

Excessive clearance

1. Inspect for the following conditions:

Worn rear bushing

Worn slip yoke bushing journal

2. Repair or replace the following components if faulty:

2008 Chevrolet Silverado 1500

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

Silverado

TRANSFER CASE CLUNK IN 4HI

between the slip yoke and
the rear bushing

Replace the slip yoke, if required. Refer to One-
Piece Propeller Shaft Replacement and Two-
Piece Propeller Shaft Replacement .

Replace the rear bushing if worn. Refer to
Transfer Case Rear Extension Bushing
Replacement .

Input shaft thrust washers

1. Inspect for worn or missing input shaft thrust washers.

2. Replace the thrust washers as required. Refer to

Transfer Case Disassemble and Transfer Case
Assemble.

Worn high speed teeth on
the high/low clutch

1. Inspect for worn high speed teeth on the high/low clutch.

Refer to High/Low Shift Components Cleaning and
Inspection.

2. Replace the high/low clutch if worn. Refer to Transfer

Case Disassemble and Transfer Case Assemble.

Rear output shaft rear
bearing outer retaining ring

1. Inspect for the following conditions:

Properly installed rear output shaft rear bearing
outer retaining ring

Excessive wear or damaged retaining ring groove in
the rear case half

2. Repair or replace the following components if found

faulty.

Properly install a new rear output shaft rear bearing
outer retaining ring.

Replace the rear case half if the retaining ring
groove is excessively worn.

Refer to Transfer Case Disassemble and
Transfer Case Assemble .

Cause

Action

DEFINITION: During acceleration or deceleration, a clunk is heard or felt in the transfer
case while in the 4HI range only.
Review the Symptoms - Transfer Case and perform the necessary inspections.

2008 Chevrolet Silverado 1500

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

Silverado

TRANSFER CASE CLUNK IN 4LO

Incorrect fluid level or
incorrect fluid

Inspect the transfer case for the correct fluid level.

Inspect the transfer case for the correct type of fluid.
Refer to Approximate Fluid Capacities .

Flush the transfer case and fill with the correct fluid, if
required. Refer to Transfer Case Fluid Replacement.

Input shaft thrust washers

1. Inspect for worn or missing input shaft thrust washers.

2. Replace the thrust washers as required. Refer to

Transfer Case Disassemble and Transfer Case
Assemble.

Rear output shaft rear
bearing outer retaining ring

1. Inspect for the following conditions:

Properly installed rear output shaft rear bearing
outer retaining ring

Excessive wear or damaged retaining ring groove in
the rear case half

2. Repair or replace the following components if found

faulty:

Properly install a new rear output shaft rear bearing
outer retaining ring.

Replace the rear case half if the retaining ring
groove is excessively worn. Refer to Transfer
Case Disassemble and Transfer Case Assemble .

Worn high speed teeth on
the high/low clutch

1. Inspect for worn high speed teeth on the high/low clutch.

Refer to High/Low Shift Components Cleaning and
Inspection.

2. Replace the high/low clutch if worn. Refer to Transfer

Case Disassemble and Transfer Case Assemble.

Cause

Correction

DEFINITION: During acceleration or deceleration, a clunk is heard or felt in the transfer
case while in the 4LO range only.
Review the Symptoms - Transfer Case and perform the necessary inspections.

1. Inspect for the following conditions:

Excessively worn planetary gears

2008 Chevrolet Silverado 1500

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

Silverado