Chevrolet Silverado / GMC Sierra. Manual — part 2881

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

TRANSFER CASE JUMPS OUT OF GEAR

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.

High/low shift fork pads

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

High/Low Shift Components Cleaning and
Inspection.

2. Replace the fork pads if worn. Refer to Transfer Case

Disassemble and Transfer Case Assemble.

Faulty high/low shift fork

1. Inspect the high/low shift fork for being damaged. Refer

to High/Low Shift Components Cleaning and
Inspection.

2. Replace the shift fork if faulty. Refer to High/Low Shift

Fork Replacement.

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

2008 Chevrolet Silverado 1500

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

Silverado