Chevrolet Silverado / GMC Sierra. Service manual — part 2929

TRANSFER CASE CLUNK DURING ACCELERATION AND DECELERATION

High/low planetary carrier
assembly

The planetary gears loose in the planetary carrier

The input shaft for missing thrust washers or
excessive thrust end play in the carrier

Excessively worn high/low clutch engagement teeth
on the carrier

Refer to High/Low Planetary Carrier Cleaning
and Inspection .

2. Replace the high/low planetary if any of the above

conditions are found. Refer to Transfer Case
Disassemble and Transfer Case Assemble.

High/low internal gear

1. Inspect the high/low internal gear to front case fit for any

looseness.

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

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

High/low clutch

1. Inspect the high/low clutch engagement teeth for

excessive wear.

2. Inspect the high/low clutch to rear output shaft splines for

excessive wear.

3. Replace the high/low clutch if faulty. 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 when it is in AWD 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.

1. Inspect for the following conditions:

2008 Chevrolet Silverado 1500

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

Silverado

TRANSFER CASE SHUDDER OR BINDING

Excessive clearance
between the slip yoke and
the rear output shaft

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 or Two-
Piece Propeller Shaft Replacement .

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

Excessive clearance
between the slip yoke and
the rear bushing

1. Inspect for the following conditions:

Worn rear bushing

Worn slip yoke bushing journal

2. Repair or replace the following components if faulty:

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

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

Cause

Correction

DEFINITION: When in the AWD mode, a shudder is felt during acceleration or a crow-
hop or binding while turning, which may cause tire scuffing.
Review the Symptoms - Transfer Case and perform the necessary inspections.
Oil breakdown or
contamination

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

Incorrect transfer case fluid

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

Burrs on the clutch hub slots

1. Inspect the clutch disc tab slots in the clutch hub for

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

2. De-burr the hub slots. If the hub slots are excessively

notched, replace the clutch hub. 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 WILL NOT SHIFT

Cause

Correction

DEFINITION: While shifting from HI range to LO range, there is gear clashing or the gear
range cannot be selected.
Review the Symptoms - Transfer Case and perform the necessary inspections.

High/low shift fork spring
assembly

1. Inspect the high/low shift fork spring assembly for the

following conditions:

Worn high/low shift fork pin

Worn cam

Broken spring

Refer to High/Low Shift Components Cleaning
and Inspection .

2. Replace the following components if found faulty:

The high/low shift fork spring assembly

The high/low shift fork pin

Refer to High/Low Shift Fork Replacement .

High/low shift fork

1. Inspect the high/low shift fork for the following

conditions:

Worn shift fork pads

Cracked or bent shift fork

Refer to High/Low Shift Components Cleaning
and Inspection .

2. Replace the following components if found faulty:

The shift fork pads

The shift fork

Refer to High/Low Shift Fork Replacement .

1. Inspect the high/low clutch for the following conditions:

Engagement teeth for burrs or damage

Sliding freely on the rear output shaft

2008 Chevrolet Silverado 1500

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

Silverado

TRANSFER CASE JUMPS OUT OF GEAR

High/low clutch

The high/low clutch collar for excessive wear

Refer to High/Low Shift Components Cleaning
and Inspection .

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

Case Disassemble and Transfer Case Assemble.

Input shaft pilot bearing
assembly

1. Inspect for the following conditions:

Failed bearing in the input shaft

Journal on the rear output shaft for excessive wear
or damage

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

2. Replace the bearing if faulty. Refer to Input Shaft Pilot

Bearing Replacement (Light Duty) or Input Shaft
Pilot Bearing Replacement (Heavy Duty and Super
Heavy Duty) .

3. Replace the rear output shaft if damaged. Refer to

Transfer Case Disassemble and Transfer Case
Assemble.

High/low planetary carrier
assembly

1. Inspect the high/low planetary engagement teeth for burrs

or damage. Refer to High/Low Planetary Carrier
Cleaning and Inspection .

2. Replace the high/low planetary carrier assembly if faulty.

Refer to Transfer Case Disassemble and Transfer
Case Assemble.

Cause

Correction

DEFINITION: Loss of the transfer case drive torque during deceleration, acceleration or
under load.
Review the Symptoms - Transfer Case and perform the necessary inspections.

1. Inspect the high/low shift fork pads for wear. Refer to

2008 Chevrolet Silverado 1500

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

Silverado