Drivetrain - Clunk Noise At A Stop Or From Launch
TECHNICALBulletin No.: 09-04-21-003D
Date: January 14, 2011
Subject: Clunk Noise at Stop or from Launch (Clean/Lubricate Rear Propshaft Slip Yoke Splines)
Models:
2007-2009 Chevrolet Silverado 1500 Series
2008-2009 Chevrolet Avalanche, Suburban, Tahoe 1500 Series
2007-2009 GMC Sierra 1500 Series
2008-2009 GMC Yukon, Yukon XL 1500 Series
Equipped with 4WD (RPO NQG, NQH)
Attention:
This bulletin contains a procedure to clean/lubricate the rear propshaft slip yoke splines and replace, if necessary. Check the history on this vehicle. If the lubrication procedure has been performed previously, then continue on and replace the transfer case rear output shaft.
Supercede:
This bulletin is being revised to update the warranty statement. Please discard Corporate Bulletin Number 09-04-21-003C (Section 04 - Driveline/Axle).
Condition
Some customers may comment on a bump feel or clunk noise at a stop or on launch. Customers may also comment that the bump feel or clunk is noticed after the vehicle has come to a complete stop and that it feels as if the vehicle was bumped from behind.
Cause
This condition may be caused by a slip/stick condition between the rear propshaft slip yoke and the transfer case rear output shaft splines. Braking to a complete stop can force the propshaft slip yoke forward into the transfer case while the vehicle rebounds slightly backward after stopping its momentum.
Correction
Note
Do not use grease for lubrication of the slip yoke splines on 4WD vehicles. The output shaft in a 4WD transfer case does not have a grease retainer to keep the grease from migrating into the transfer case and mixing with the fluid inside. Grease is not compatible with the automatic transmission fluid (ATF) used in the transfer case and can cause damage if mixed.
Note
The clunk noise may also be due to fuel movement in the fuel tank when not completely full. If the condition is eliminated after filling the fuel tank, the noise is isolated to the fuel movement in the tank. Please make no repair attempts, as this noise is considered an operating characteristic.
Verify the customer's concern.
Clean/Lubricate Rear PropShaft Slip Yoke Splines
1. Remove the rear drive shaft. Refer to One-Piece Propeller Shaft Replacement in SI.
2. Inspect the rear propshaft slip yoke splines.
Note
Protect the transfer case rear seal from Brake Clean.
3. Clean the rear propshaft slip yoke splines with Brake Clean or equivalent and a shop towel.
4. Assure that the splines are free of rust or other foreign material.
5. Lubricate the spline with Automatic Transmission Fluid, P/N 88861003 (in Canada, 19264717).
6. Reinstall the rear drive shaft. Refer to One-Piece Propeller Shaft Replacement in SI.
7. Road test the vehicle and verify that the noise is gone.
8. If the vehicle has a repeat concern after lubricating the slip yoke splines, replace the rear output shaft.
Replace Transfer Case Rear Output Shaft
Note
Do Not replace the output shaft unless the cleaning and lubrication procedure is ineffective.
1. Remove the transfer case assembly. Refer to Transfer Case Assembly Replacement in SI.
2. Disassemble the transfer case. Refer to Transfer Case Disassemble in SI.
3. Replace the transfer case rear output shaft. Refer to the Parts Information below.
4. Assemble the transfer case.
5. Reinstall the transfer case assembly.
Parts Information
Warranty Information
For vehicles repaired under warranty, use the table.
Disclaimer