Silverado - thunk, clunk, shunk

Okay, a while ago you were talking about a clunk in the rearend of these rigs, and I was going to have my checked out for the problem described. However, I didn't copy the info down, and now I forget what the suggested
remedy was -- something about lubing the splines, removing the driveline, yadda, yadda. Sorry.
But let me tell you what my problem is. This '00 Silver has 94k miles, allegedly mostly highway (makes sense). When pulling to a stop in town, I feel a thunk (but really don't hear anything), akin to what a novice (me) might think was significant play in the universal joint. Very similar feeling when moving from that stop. A slight "clunk" sound can be heard, but it is much more the feel of a thunk. Sorry, does this make any sense?
Any suggestions on where to begin?
Your thoughts are appreciated. TX!
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I had the exact same problem. I was told it was the leaf springs, shackles, shocks, and even the brakes. It was none of them. I came here and was told to check my Slip Yoke, and that's what it was. I had a buddy pull it out, grease it with mobile 1 synthetic grease, and it went away. Most of the time I understand it comes back after a few months or so, I guess the only real fix is buying the nickel plated replacement but it costs allot. This was on a 93, so I could be wrong.... -- ---------------------------------------------------------------- Ed Murray Certified Locksmith My Enthusiast's Website: http://www.crooked-ridez.com

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Slip yoke binding on the output shaft splines. Just remove the driveshaft from the tranny (2WD) or transfer case (4WD), slop some grease inside the yoke, and reassemble.
Doc

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Hey Doc, I climbed under there to take a look. The slip yoke has a bellows rubber sleeve with a factory clamp at each end. The factory clamp looks like it requires a special tool to install. Question is; if I cut the clamp off on end to get at the yoke, will a screw worm type ss clamp be ok or will it throw the drive out of balance? Mine is still under warranty, but will not be taking it to the dealer until the spring thaw. Thanks, MR
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these
suggested
driveline,
town, I

(me)
heard,
sense?
driveshaft
Does the factory clamp look like the same kind they use on the CV boots? If so, A CV clamp tool would to the trick. Otherwise, I see no reason why a good-ol worm drive wouldn't work.
Doc
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"MR" wrote

Is this a 4X4? If so, you are looking at the front driveshaft. This is not the driveshaft that causes the clunking noise. If you are seeing this rubber sleeve on the rear driveshaft, you must have a two piece driveshaft. In this case, the clunking noise is not from the slip yoke, as the two piece driveshafts don't have this problem. Plus, the two piece shafts usually have a grease nipple on the yoke.
Ian
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On Sat, 10 Jan 2004 17:29:45 GMT, "shiden_kai"

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. Thanks MR
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"MR" wrote

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 Nm (52 lb ft). b.. Tighten the center bearing support nuts to 40 Nm (30 lb ft). 5.. After completing the repair, operate the vehicle in order to verify that the condition has been corrected. Ian
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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
On Sat, 10 Jan 2004 18:26:49 GMT, "shiden_kai"

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"MR" wrote

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
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On Sat, 10 Jan 2004 23:44:18 GMT, "shiden_kai"

Thanks. I may do that after it warms a little. Been below 0 the last few days. MR
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