Chevrolet Silverado / GMC Sierra. Service manual — part 2880

2. Turn the switch clockwise past 4 low into the neutral request mode and hold for 30 seconds.

3. An audible noise from the motor should occur indicating a successful learn procedure.

TRANSFER CASE POPPING NOISE

TRANSFER CASE WHINE OR RUMBLE NOISE

TRANSFER CASE GROWL OR GRINDING NOISE

Cause

Correction

DEFINITION: A faulty internal transfer case component that causes a popping noise in the
transfer case.
Review the Symptoms - Transfer Case and perform the necessary inspections.

Chain jump

Replace the chain and sprockets. Refer to Transfer Case
Disassemble and Transfer Case Assemble.

Replace the shaft bearings. Refer to Transfer Case
Disassemble and Transfer Case Assemble.

Inspect for damaged components caused by metal debris.
Refer to Drive Chain, Drive Sprocket, and Driven
Sprocket Cleaning and Inspection and Front Output
Shaft and Input Shaft Cleaning and Inspection.

Cause

Correction

DEFINITION: A faulty internal transfer case component that causes a whine or rumbling
noise in the transfer case.
Review the Symptoms - Transfer Case and perform the necessary inspections.

Faulty bearings

1. Inspect all of the bearings and journals. Refer to Rear

Output Shaft Cleaning and Inspection, Front
Output Shaft and Input Shaft Cleaning and
Inspection, and Drive Chain, Drive Sprocket, and
Driven Sprocket Cleaning and Inspection.

2. Replace any faulty bearings and any components with

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

Cause

Correction

DEFINITION: A faulty internal transfer case component that causes a growl or grinding

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Transfer Case - MP 1625/1626-NQF - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &

Silverado

noise in the transfer case while the vehicle is turning or in a four wheel drive mode.
Review the Symptoms - Transfer Case and perform the necessary inspections.

High/low planetary carrier
assembly

1. Inspect the high/low planetary carrier assembly for the

following conditions:

Chipped, bent, or deformed teeth

Planetary gear needle bearings worn

Planetary gear thrust washer cracked or missing

Seized or binding planetary gears

Refer to High/Low Planetary Carrier Cleaning
and Inspection .

2. Replace the high/low planetary carrier assembly if any of

the above conditions exist. Refer to Transfer Case
Disassemble and Transfer Case Assemble.

Input shaft

1. Inspect the input shaft in the planetary carrier assembly

for excessive thrust end play.

2. Inspect the input shaft teeth for the following conditions:

Damage

Worn or galled thrust surfaces

Excessive wear

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.

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

conditions:

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Transfer Case - MP 1625/1626-NQF - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &

Silverado

TRANSFER CASE CLUNK IN 2HI ONLY

High/low internal gear

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: During acceleration or deceleration, a clunk is heard or felt in the transfer
case.
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 .

1. Inspect for the following conditions:

Worn rear bushing

2008 Chevrolet Silverado 1500

2008 TRANSMISSION Transfer Case - MP 1625/1626-NQF - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &

Silverado

TRANSFER CASE CLUNK IN 4HI

Excessive clearance
between the slip yoke and
the 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 .

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

Correction

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 1625/1626-NQF - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &

Silverado