Chevrolet Silverado / GMC Sierra. Service manual — part 2881

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.

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.

2/4 wheel drive
synchronizer assembly

1. Inspect the synchronizer for the following conditions:

The synchronizer hub internal teeth to rear output
shaft splines for excessive looseness caused by wear

The synchronizer sleeve engagement teeth to the
drive sprocket for wear

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

2. Replace the synchronizer assembly if faulty. 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

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

Refer to High/Low Shift Components Cleaning and

2008 Chevrolet Silverado 1500

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

Silverado

TRANSFER CASE CLUNK IN 4LO

TRANSFER CASE WILL NOT SHIFT

the high/low clutch

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.

High/low planetary carrier
assembly

1. Inspect for the following conditions:

Excessively worn planetary gears

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.

2008 Chevrolet Silverado 1500

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

Silverado

Cause

Correction

DEFINITION: While shifting from HI range to LO range, there is gear clashing or no HI
range; or the transfer case will not shift from 2 wheel drive to 4 wheel drive.
Review the Symptoms - Transfer Case and perform the necessary inspections.

Mode shift clash

1. Disassemble the transfer case. Refer to Transfer Case

Disassemble.

2. Inspect the synchronizer for being faulty. Refer to

Two/Four Wheel Drive Shift Components Cleaning
and Inspection.

3. Replace the synchronizer if faulty. Refer to Transfer

Case Assemble.

Mode block

1. Disassemble the transfer case. Refer to Transfer Case

Disassemble.

2. Inspect the synchronizer sleeve for sliding freely on the

synchronizer hub.

3. Inspect the synchronizer sleeve or synchronizer hub for

being faulty.

4. Replace the synchronizer sleeve or synchronizer hub if

faulty. Refer to Transfer Case Assemble.

If the symptoms occur during cold temperatures, flush and fill
the front axle with synthetic fluid. Refer to Front Axle
Lubricant Level Inspection (9.25 Inch Axle) .

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

2008 Chevrolet Silverado 1500

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

Silverado

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 .

High/low clutch

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

Engagement teeth for burrs or damage

Sliding freely on the rear output shaft

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 input shaft pilot 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 (Heavy Duty and Super Heavy
Duty) .

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

2008 Chevrolet Silverado 1500

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

Silverado