Silverado – thunk, clunk, shunk
Question:
“MR” wrote: Thanks for the info Ian. Mine does not seem to have the launch shudder as descirbed, but does have a slight clunk like it has slipped and caught just as it starts off. It only does it after it has been on the hwy. and very warm. It has the locking rear end, but don’t know if that has anything to do with it. Any ideas or is that the start of the launch shudder? I have about 15k miles on it now and only use it to tow a travel trailer in season. I guess the only other option would be to try greasing that slip yoke. You could cut off the original style clamp and just use a screw type clamp as a replacement. I’m not sure that greasing this slip yoke will help any, but you never know. Ian
Thanks. I may do that after it warms a little. Been below 0 the last few days. MR
Response:
Thanks for the info Ian. Mine does not seem to have the launch shudder as descirbed, but does have a slight clunk like it has slipped and caught just as it starts off. It only does it after it has been on the hwy. and very warm. It has the locking rear end, but don’t know if that has anything to do with it. Any ideas or is that the start of the launch shudder? I have about 15k miles on it now and only use it to tow a travel trailer in season. Thanks, MR “MR” wrote: Right. This is a two piece drive shaft on 2wd, 02 2500HD. The yoke is covered with the sleeve just behind the support bearing. I looked for a grease fitting, but did not see one or anyway to apply grease without taking the sleeve and drive shaft out. No g-fittings on the u-joints either. Ok, the slip yoke issue doesn’t apply to this truck. There is however a bulletin on “launch shudder” which applies to your truck. Perhaps this is the problem you are experiencing. I’ll quote the bulletin below. Launch Shudder/Vibration on Acceleration (Replace Propeller Shaft and InstallNew Pinion Flange/Seal) #02-04-17-001A – (07/19/2002) Launch Shudder/Vibration on Acceleration (Replace Propeller Shaft and Install New Pinion Flange/Seal) 1999-2003 Chevrolet Silverado 2WD 1500 Series Extended Cab Short Box Pickups 1999-2003 GMC Sierra 2WD 1500 Series Extended Cab Short Box Pickups With 4L60-E Automatic Transmission (RPO M30) Except QUADRASTEERT (RPO NYS) Equipped Vehicles This bulletin is being revised to add Model information. Please discard Corporate Bulletin Number 02-04-17-001 (Section 04 — Driveline Axle). Important Implementation of this Service Bulletin by “GM of Canada” dealers requires prior District Service Manager approval. Condition Some customers may comment on a vibration when accelerating from a stop. This is also known as launch shudder. This condition may occur between 0-40 km/h (0-25 mph) and be more noticeable when the vehicle is carrying cargo or used for towing. Correction A new propeller shaft, P/N 15071486, has been developed to correct this condition. The new propeller shaft incorporates dual double cardan joints on the center and rear joint positions. Refer to Corporate Bulletin Number 02-00-90-002 for lubrication information. The new propeller shaft will require the installation of a new pinion flange kit, P/N 15071485. The pinion flange kit consists of the following components: a.. A pinion flange b.. Hex bolts (four) c.. A pinion seal d.. A rear axle drive pinion nut Replace the propeller shaft with the new propeller shaft using the following procedure. Use the part numbers listed below. 1.. Remove the propeller shaft assembly and the center bearing. Refer to the applicable Propeller Shaft Replacement procedure in the Propeller Shaft sub-section of the Service Information (SI). Important In step 2, you must measure the pinion and differential preload. This information is needed to set the preload of the new pinion flange to the correct specification and to reduce any rear axle noise concerns. 2.. Remove the drive pinion yoke and the pinion oil seal. Refer to the Drive Pinion Flange/Yoke and/or Oil Seal Replacement procedure in the Rear Drive Axle sub-section of the Service Information (SI). Important In step 3, use this procedure as a guideline to install the pinion flange to the drive pinion and to set up the proper pinion bearing preload. 3.. Install the new pinion oil seal, the new pinion flange and the new drive pinion nut. Refer to the Drive Pinion Flange/Yoke and/or Oil Seal Replacement procedure in the Rear Drive Axle sub-section of the Service Information (SI). 4.. Install the new propeller shaft assembly and the new center bearing. Refer to the applicable Propeller Shaft Replacement procedure in the Propeller Shaft sub-section of the Service Information (SI). Tighten a.. Tighten the propeller shaft flange bolts to 70 N.
