01 Denali Driveline Problem

mumzer · February 6, 2008

I have an 01 Denali XL that once warmed up after a freeway drive begins to clunk and shudder at high turning angles and low speeds. It feels just like a binding LSD with the wrong friction modifier in it, but the sensation kinda feels like its coming from the front axle (which i believe is open).

I am aware of the TSB for the eaton, and recently changed fluid in the diff with the correct fluid. Truck still chatters.

Could this symptom be caused by a failing transfer case clutch pack as well, or is a problem with differentiation always in the rear end?

thanks

bobcat5544 · February 6, 2008

Document ID# 1646448

2001 GMC Truck Yukon Denali

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Subject: Shudder on Turns - keywords 136 236 246 4WD automatic AWD bind case contaminated NP4 NP8 vibration #PIP3012D - (04/12/2005)

Models: 1999-2005 Chevrolet Astro (AWD)

1999-2005 GMC Safari (AWD)

1998-2001 Oldsmobile Bravada

with All-Wheel Drive (NV136) Transfer Case (RPO NP4)

1999-2004 Chevrolet Blazer

1999-2003 Chevrolet S-10

1999-2001 GMC Envoy

1999-2004 GMC Jimmy

1999-2003 GMC Sonoma

with Four Wheel Drive (NVG236) Transfer Case (RPO NP8)

1999-2000 Cadillac Escalade

2002 Chevrolet Avalanche

1999 GMC Suburban

1999-2002 GMC Sierra, Yukon, Yukon XL, Denali

with Four Wheel Drive (NVG246) Transfer Case (RPO NP8)

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The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in the PI.

Condition/Concern:

The NVG 136 All Wheel Drive (AWD) Transfer Case and the 236 and 246 NVG Selectable Transfer Cases operating in the Auto Mode may exhibit a condition of a vibration/shudder during low speed turns such as a parking lot maneuver, up to approximately 5 MPH (8 km/h).

Recommendation/Instructions:

Note: Review TSB 99-04-21-005B (or any superseded version of this TSB) and change the Transfer Case fluid regardless of which category the vehicle falls into and even if the fluid was previously changed.

Drive the vehicle a minimum of 5 miles (8 km) to obtain operating temperature. Once at operating temperature drive the vehicle into a tight turn just short of the steering wheel lock/stop at a speed of less than 5 MPH (8 km/h). If the shudder is present perform the following diagnostics.

1. Remove the TCCM fuse and see if the condition is gone. If the condition is gone, then proceed to step 2. If the condition is unchanged, then skip to step 4.

2. If the condition is gone, begin swapping the wheels and tires from an identically built vehicle that does not exhibit the concern and re-evaluate the condition.

3. If removing the TCCM fuse corrects the condition and swapping tires from another identically built vehicle does not improve the concern, then proceed with the following.

NVG136

• Inspect the TCCM for module part numbers and replace as required.

• 98-01 Oldsmobile Bravada - 15748801 (or any superseded number).

• 99-01 Chevrolet Astro, GMC Safari - 15748744 (or any superseded number).

NVG 236

• Inspect the TCCM for module part number 15748800 (or any superseded number) and replace as required.

• 99 - 01 Chevrolet Blazer and S10, GMC Envoy Jimmy and Sonoma.

NVG 246

• Inspection of the TCCM is not required.

• 99-02 Cadillac Escalade, Chevrolet Suburban Silverado Tahoe, GMC Sierra Yukon XL Yukon.

4. If the shudder was not eliminated by removing the ATC/TCCM fuse, remove the encoder motor from the transfer case and test drive the vehicle again at operating temperature.

• If the shudder is eliminated, replace the encoder motor.

• If the shudder was not eliminated, reinstall the encoder motor and fuse. Verify the shudder is still present and remove the front prop shaft.

• Drive the vehicle at operating temperature with the front prop shaft removed, if the condition is still present and the vehicle is equipped with a G80 locking differential . The axle fluid should changed and driven in several left and right hand circles then driven at least 50 miles (80 kms) under normal driving to remove any glazing from differential clutches.

5. If the above steps have not eliminated the shudder condition, the transfer case clutch pack needs re-shimmed. To perform the shimming procedure use Service Information (eSI).

Note: When performing the shim selection process eSI indicates to select a shim(s) + or - .004 in. (0.10 mm). On a 136 Transfer Case, the shim(s) should be - 0.004 in. (0.10 mm) for best performance

Please follow this diagnosis process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

mumzer · February 6, 2008

pretty sure the denali uses the 149 transfer case (AWD) not the one described above...

any other suggestions?

bobcat5544 · February 6, 2008

My bad it is a 149.

GM has a few bulletins to try.

1st one give you the order to start from.

Document ID# 1813671

2005 GMC Truck Yukon Denali

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Subject: NP3 NVG149 Transfer Case Bind or Shudder on Turns - keywords differential growl grind G80 lock transfercase vibration #PIP3132C - (04/07/2006)

Models: 2002-2004 Cadillac Escalade, Escalade EXT

2004-2006 Chevrolet Silverado

2000-2006 GMC Yukon Denali, Yukon XL Denali

2001 GMC Sierra

2003-2006 GMC Sierra Denali

Equipped with NVG149 (RPO - NP3) Transfer Case

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The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:

Light duty trucks and utilities equipped with an RPO code NP3 NVG149 transfer case may exhibit a bind or shudder on turns.

Recommendation/Instructions:

Diagnosis for this concern should start by checking for possible mismatched tires by swapping the wheels and tires from a properly functioning vehicle for testing purposes. If the tire check does not repair the concern, next test the transfer case viscous coupling as per eSI Document ID # 874570. If the transfer case passes the viscous coupling test, check to see if the vehicle is equipped with a G80 locking differential or a limited slip differential. If it is, refer to locking rear differential diagnosis in eSI Document ID # 703405 or limited slip differential diagnosis eSI Document ID # 820995. If the locking differential or limited slip differential is functioning properly, a steering or suspension issue could be causing the concern.

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Document ID# 874570

Transfer Case Viscous Coupling Test

Tools Required

J 45382 Transfer Case Tester

Important:

• Do not operate the vehicle on a hoist to diagnose the driveline components. Operating the vehicle on a hoist can cause over-spinning of the planetary pinion gears.

• Testing the viscous coupling operation by removing a propeller shaft and driving the vehicle causes the viscous coupling to fail.

To determine if the viscous coupling is operating correctly, use the following test procedure. The test determines if the viscous coupling is faulty from a totally locked up failure, or if the viscous coupling fluid has leaked out from being severely humped.

Important: The Viscous Coupling Test is very sensitive to the temperature of the transfer case. If the transfer case is very hot, the time to turn will be faster. If the transfer case is cold, the time to turn will be slower.

Operate the vehicle for 24 km (15 mi), or until normal operating temperatures are reached.

Set the parking brakes for the rear wheels.

Position the transmission in NEUTRAL.

Raise the vehicle. Refer to Lifting and Jacking the Vehicle .

Remove the front propeller shaft. Refer to Front Propeller Shaft Replacement .

Install the J 45382 into the transfer case front output shaft.

Using a torque wrench at 11 N·m (100 lb in) on the J 45382 , turn the front output shaft 90 degrees.

Note the length of time it takes to turn the front output shaft the 90 degrees.

• If the front output shaft turns slow, and takes at least 10 seconds, the viscous coupling is operating correctly.

• If the front output shaft will not turn, the viscous coupling or the planetary carrier assembly could be locked-up.

• If the front output shaft turns easily, and the 11 N·m (100 lb in) cannot be obtained, the viscous coupling is faulty.

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Document ID# 703405

Locking Differential Diagnosis

1. Place the vehicle on a frame-contact hoist, allowing free rotation of the rear wheels.

2. Hold 1 wheel stationary. Slowly rotate the other wheel approximately 1/2 revolution per second in both the forward and reversed directions. The wheel should rotate freely. The differential is locking and is broken if both wheels attempt to turn together.

3. Raise the hoist to maximum height with 1 person in the vehicle.

4. Start the engine. Ensure that the engine is operating at low idle speed (warm engine).

5. Apply the service brake. Place the automatic transmission in drive. Depress the clutch and place the transmission in first gear with a manual transmission.

6. Lock 1 rear wheel by pulling one parking brake cable from under the vehicle with the aid of an assistant.

7. Release the service brakes or disengage the clutch slowly enough to start the free wheel turning. The locked rear wheel remains stationary.

8. Increase the speed of the free wheel. The differential will lock, causing the rotating wheel to stop or both wheels to turn at the same speed. The engine, if equipped with manual transmission, may stall. In order to cause the differential to lock, you may need to accelerate the engine until approximately 16 km/h (10 mph) is indicated on the vehicle speedometer. If the indicated speed can be increased beyond 32 km/h (20 mph) without causing the differential to lock, the unit is not functioning properly. Rapid release of the brakes or clutch, or rapid acceleration of the engine, will invalidate the test.

9. Lock the opposite rear wheel and repeat the procedure.

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mumzer · February 6, 2008

many thanks...i hope like hell its the clutches in the diff. it seems to be temp related, so im afraid its not.

My bad it is a 149.

GM has a few bulletins to try.

1st one give you the order to start from.

Document ID# 1813671

2005 GMC Truck Yukon Denali

--------------------------------------------------------------------------------

Subject: NP3 NVG149 Transfer Case Bind or Shudder on Turns - keywords differential growl grind G80 lock transfercase vibration #PIP3132C - (04/07/2006)

Models: 2002-2004 Cadillac Escalade, Escalade EXT

2004-2006 Chevrolet Silverado

2000-2006 GMC Yukon Denali, Yukon XL Denali

2001 GMC Sierra

2003-2006 GMC Sierra Denali

Equipped with NVG149 (RPO - NP3) Transfer Case

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The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:

Light duty trucks and utilities equipped with an RPO code NP3 NVG149 transfer case may exhibit a bind or shudder on turns.

Recommendation/Instructions:

Diagnosis for this concern should start by checking for possible mismatched tires by swapping the wheels and tires from a properly functioning vehicle for testing purposes. If the tire check does not repair the concern, next test the transfer case viscous coupling as per eSI Document ID # 874570. If the transfer case passes the viscous coupling test, check to see if the vehicle is equipped with a G80 locking differential or a limited slip differential. If it is, refer to locking rear differential diagnosis in eSI Document ID # 703405 or limited slip differential diagnosis eSI Document ID # 820995. If the locking differential or limited slip differential is functioning properly, a steering or suspension issue could be causing the concern.

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Document ID# 874570

Transfer Case Viscous Coupling Test

Tools Required

J 45382 Transfer Case Tester

Important:

• Do not operate the vehicle on a hoist to diagnose the driveline components. Operating the vehicle on a hoist can cause over-spinning of the planetary pinion gears.

• Testing the viscous coupling operation by removing a propeller shaft and driving the vehicle causes the viscous coupling to fail.

To determine if the viscous coupling is operating correctly, use the following test procedure. The test determines if the viscous coupling is faulty from a totally locked up failure, or if the viscous coupling fluid has leaked out from being severely humped.

Important: The Viscous Coupling Test is very sensitive to the temperature of the transfer case. If the transfer case is very hot, the time to turn will be faster. If the transfer case is cold, the time to turn will be slower.

Operate the vehicle for 24 km (15 mi), or until normal operating temperatures are reached.

Set the parking brakes for the rear wheels.

Position the transmission in NEUTRAL.

Raise the vehicle. Refer to Lifting and Jacking the Vehicle .

Remove the front propeller shaft. Refer to Front Propeller Shaft Replacement .

Install the J 45382 into the transfer case front output shaft.

Using a torque wrench at 11 N·m (100 lb in) on the J 45382 , turn the front output shaft 90 degrees.

Note the length of time it takes to turn the front output shaft the 90 degrees.

• If the front output shaft turns slow, and takes at least 10 seconds, the viscous coupling is operating correctly.

• If the front output shaft will not turn, the viscous coupling or the planetary carrier assembly could be locked-up.

• If the front output shaft turns easily, and the 11 N·m (100 lb in) cannot be obtained, the viscous coupling is faulty.

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Document ID# 703405

Locking Differential Diagnosis

1. Place the vehicle on a frame-contact hoist, allowing free rotation of the rear wheels.

2. Hold 1 wheel stationary. Slowly rotate the other wheel approximately 1/2 revolution per second in both the forward and reversed directions. The wheel should rotate freely. The differential is locking and is broken if both wheels attempt to turn together.

3. Raise the hoist to maximum height with 1 person in the vehicle.

4. Start the engine. Ensure that the engine is operating at low idle speed (warm engine).

5. Apply the service brake. Place the automatic transmission in drive. Depress the clutch and place the transmission in first gear with a manual transmission.

6. Lock 1 rear wheel by pulling one parking brake cable from under the vehicle with the aid of an assistant.

7. Release the service brakes or disengage the clutch slowly enough to start the free wheel turning. The locked rear wheel remains stationary.

8. Increase the speed of the free wheel. The differential will lock, causing the rotating wheel to stop or both wheels to turn at the same speed. The engine, if equipped with manual transmission, may stall. In order to cause the differential to lock, you may need to accelerate the engine until approximately 16 km/h (10 mph) is indicated on the vehicle speedometer. If the indicated speed can be increased beyond 32 km/h (20 mph) without causing the differential to lock, the unit is not functioning properly. Rapid release of the brakes or clutch, or rapid acceleration of the engine, will invalidate the test.

9. Lock the opposite rear wheel and repeat the procedure.

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