4WD cannot use grease due to use of Auto Track II in TC. (I've posted the info below.) I just serviced the front/rear differentials and transfer case. No pump rub hole in the TC yet and I'll be doing the TC pump upgrade in the near future. Transfer Case Pump Upgrade parts and watch the "Chevy and GMC Transfer Case Problem" video.
I pulled the driveshaft, cleaned the splines, got off all the rust, etc. and coated it in Auto Track II fluid. (The Auto Track won't "lube" it the way I want but grease will migrate into the TC on 4WD models. After I put it all back together, I still get the clunk. So it's not binding after being cleaned and the bulletin states to "replace the transfer case rear output shaft." Holy hell! Why?!? I have noticed that the clunk sound is coming from inside the TC toward the middle, so probably is a bad shaft which is obviously known by GM to be defective. If you couple the bad TC output shaft with the bad pump assembly which will eat a hole through the case, shouldn't GM have issued a recall and addressed them both at the same time. EVERYONE has these issues!!!!!!!!!!!!! Oh....good luck finding a rear output shaft for the NP246 Transfer Case.
#09-04-21-003B: Clunk Noise at Stop or From Launch (Clean/Lubricate Rear Propshaft Slip Yoke Splines) - (Aug 11, 2009)
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.
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: 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
Remove the rear drive shaft. Refer to One-Piece Propeller Shaft Replacement in SI.
Inspect the rear propshaft slip yoke splines.
Note: Protect the transfer case rear seal from Brake Clean.
Clean the rear propshaft slip yoke splines with Brake Clean or equivalent and a shop towel.
Assure that the splines are free of rust or other foreign material.
Lubricate the spline with Automatic Transmission Fluid, P/N 88861003 (in Canada, 88861004).
Reinstall the rear drive shaft. Refer to One-Piece Propeller Shaft Replacement in SI.
Road test the vehicle and verify that the noise is gone.
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.
Remove the transfer case assembly. Refer to Transfer Case Assembly Replacement in SI.
Disassemble the transfer case. Refer to Transfer Case Disassemble in SI.
Replace the transfer case rear output shaft. Refer to the Parts Information below.
Assemble the transfer case.
Reinstall the transfer case assembly.
Parts Information:
19133059 - SHAFT, TRFER CASE (RPO NQH)
19133061 - SHAFT, TRFER CASE (RPO NQG)
88861003 (in Canada, 88861004) - Automatic Transmission Fluid
I pulled the driveshaft, cleaned the splines, got off all the rust, etc. and coated it in Auto Track II fluid. (The Auto Track won't "lube" it the way I want but grease will migrate into the TC on 4WD models. After I put it all back together, I still get the clunk. So it's not binding after being cleaned and the bulletin states to "replace the transfer case rear output shaft." Holy hell! Why?!? I have noticed that the clunk sound is coming from inside the TC toward the middle, so probably is a bad shaft which is obviously known by GM to be defective. If you couple the bad TC output shaft with the bad pump assembly which will eat a hole through the case, shouldn't GM have issued a recall and addressed them both at the same time. EVERYONE has these issues!!!!!!!!!!!!! Oh....good luck finding a rear output shaft for the NP246 Transfer Case.
#09-04-21-003B: Clunk Noise at Stop or From Launch (Clean/Lubricate Rear Propshaft Slip Yoke Splines) - (Aug 11, 2009)
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.
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: 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
Remove the rear drive shaft. Refer to One-Piece Propeller Shaft Replacement in SI.
Inspect the rear propshaft slip yoke splines.
Note: Protect the transfer case rear seal from Brake Clean.
Clean the rear propshaft slip yoke splines with Brake Clean or equivalent and a shop towel.
Assure that the splines are free of rust or other foreign material.
Lubricate the spline with Automatic Transmission Fluid, P/N 88861003 (in Canada, 88861004).
Reinstall the rear drive shaft. Refer to One-Piece Propeller Shaft Replacement in SI.
Road test the vehicle and verify that the noise is gone.
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.
Remove the transfer case assembly. Refer to Transfer Case Assembly Replacement in SI.
Disassemble the transfer case. Refer to Transfer Case Disassemble in SI.
Replace the transfer case rear output shaft. Refer to the Parts Information below.
Assemble the transfer case.
Reinstall the transfer case assembly.
Parts Information:
19133059 - SHAFT, TRFER CASE (RPO NQH)
19133061 - SHAFT, TRFER CASE (RPO NQG)
88861003 (in Canada, 88861004) - Automatic Transmission Fluid
