DaveRaune & Jimamatic - Driveline Clunk

[Billy14]

Hey guys,

After replacing my two piece shaft with the single I had the clunk at stop & start so bad it would almost jar your teeth. I have posted the FIX at least 5 times but can't find my past posts even with the search tool. Hmmmmmmmm!

I'll lay down the basics briefly, but if you have anymore questions send me an Email at the address listed in my signature.

First of all when I figured out what was causing the clunk I tried high quality bearing grease. Smooth as silk for a couple of weeks, then came back. Went to my dealer & THEY gave me a special very sticky cherry colored grease they say they use on Tahoes for the same problem. Can't seem to get the name of it from them. TALK TO YOUR DEALER

Problem - The slip yoke connecting the drive shaft to the tranny output spline in the transfer case is binding when the system unwinds. When the load exceeds the friction point of the splines the slip yoke finally breaks free giving us the dreaded clunk.

Fix:
1) Remove the driveshaft. Mark the Ujoint caps & driveshaft with relation to the differential yoke (an old habit but probably will make no difference either way). I believe the cap bolts take an 11mm wrench.

2) Pull the shaft & slip yoke out of the transfer case. I've done this three times & have not lost a drop of fluid.

3) Take a can of spray-on brake cleaner & thouroughly wash out all fluid & metal shavings out of the FEMALE end of the slip yoke attached to the drive shaft. Allow time for all the cleaner to evaporate completely. I did nothing to the male end in the transfer case.

4) Take a wooden tongue depressor & spread a golf ball size amount of the special grease into the ridges & valleys of the spline teeth from the mouth down to about 4 to 5 inches.

5) Install the yoke back in the transfer case & slide back & fourth a few times. Attach back to the diff. yoke & tighten both caps.

Now you can enjoy a super smooth ride accomodating both stops & starts. After applying the special grease acquired from my dealer, I now have 2 months & about 4,500 miles with no signs of the clunk coming back to haunt me. If it does, I'll let all know.

Billy

[ 06-01-2002: Message edited by: Billy14 ]

[ 06-01-2002: Message edited by: Billy14 ]</p>

[Jimamatic]

Thanks Billy14. Sounds like problem solved...
When I go to get the new D/L, I'll try to have them do this. It blows my mind that GM let these
trucks out the door like this. Seems like a very
minimum requirement. You know like engine oil, tranny fluid, rear diff lube, chassis lube, etc..... Anywho, thanks again.

[Kent Tuttle]

I have the clunk during stopping and starting but the truck is a CC 2wd with two piece drive shaft. Guess I need to visit the dealer and see what's up?? Unless someone knows of a fix??

[mguebert]

I also have the drivline clunk, mostly at takeoff but occasionally stopping as well. Mine is a ext cab lb 2wd. I have had it to two different dealers and both told me it was normal :mad: :mad: :mad:

Since when is it normal for a $30000 plus vehicle of any kind to do something like this.

[Billy14]

mguebert,

Do you have the single shaft or the two piece.

If you have the single, this procedure DOES work. They have had the same problem on the 1500 series trucks & replaced the slip yokes with a nickel plated one. According to GM, they have no intention of doing the same to the HD's to date.

Billy

On Edit, I put the cart before the horse & just now read your signature. Don't know if this would help on an ext. cab but for only 30 minutes of your time or the dealer's, it sure would be worth a shot.

[ 06-03-2002: Message edited by: Billy14 ]</p>

[Derek M]

Things to note.....

I have a 2500HD 2wd LB with 2 piece shaft of course.

I've got the clunk/bump also, but I believe the cause may be from a different location than with the 1 piece DS.

I need your guys help in finding the differences between the 1 piece DS and 2 piece DS.

On my truck the output shaft on the transmission covered from what appears to be a slip yoke. Ohh but what is this? the center of the yoke has a bolt. This bolt has the head located on the inside by the u-joint. The threads of this bolt appear to extend through the yoke and into the output shaft of the transmission. So with the two piece setup does this yoke actually slip? or does this bolt prevent slippage/movement? It would appear the bolt inhibits this yoke from moving front to back on the output shaft.

On the DS connection going into the rear diff the DS and rear pinion yoke don't have any slip function.

In the middle of the truck where the two shafts meet it appears, under this black slinky like dust cover, that this is the point where slip occurs. Rotating the DS side to side seems there's around 15-17 thousands of slack in the his middle slip joint, could this be where the problem is coming from? Removing the DS from the diff the middle slip joint between the two shafts is pretty easily moved front to back surprising how easy it is actually to move the rear shaft front to back. Almost feels like there's a spring pushing the rear DS back toward the rear of the truck, but again the load of the spring seems very soft. Could this be the cause?

I would like to pull the dust cover off the mating point of the two driveshafts, but there's two proprietary metal retainers that look like one time use items. These retainers appear to hold the dust cover in place. I'd like to lube this area if possible, but I don't wanna take the dust cover off and not be able to install it back correctly without the proper retaining clips.

Anyone? thoughts?

[ 06-04-2002: Message edited by: Derek M ]</p>

[EIS01]

My friend is a mechanic at our local Chevy dealership. He told me he replaced a part in the drive line. It costs over a $100.00 just for the part. The new design is much better and removes the clunk. He told me, he will give me a copy of the bulletin that is now out for our trucks. I am not sure if it applies to all, or just the one piece drive shaft\short beds. I believe it was the U-Joint, but I will have to find out. I am mechanically challenged. smile.gif Have a great day, Kevin

By the way, He was real pleased with the fix.

[Kent Tuttle]

Great info! Keep us posted on what they fixed/replaced and what bulletin if any.

[Jimamatic]

A bulletin for the slip/clunk... I like it.
Can't wait to see it. It would be nice to get
the one piece and the clunk fixed in my truck
with only one visit to the dealership.

[BradL]

To all,

I had my truck into the dealer this morning to have the procedure performed as Billy14 described. Of course the use of a lift makes all the difference, but it's a 30 minute job.

I visited with the tech while he did the job. He said I had "a little" grease left from the original install of the 1 piece back in Dec 01, which was 6 or 7,000 miles ago. No wonder the thing was jarring my teeth at every start/stop.

I would say the new grease is a deep purple color vs a cherry color, but regardless it is a very tacky grease - put your finger in it and pull away and it sticks like glue.

It is amazing how much smoother the truck is now. Hope this lasts longer than 5,000 miles!

[DaveRuane]

Thanks all! Does anyone have a part# for this "sticky, cherry-red, or grape-colored, grease"

Please let me know the part# or how to reference it at the dealer or auto parts store. I'd just as soon fix it myself! Thanks - Dave

[BradL]

Wish I could give you a part # for the grease, but the tech was using a standard grease gun to dispense the grease when he did mine, so I didn't get to see the cartridge before it was placed in the gun.

I'll try to follow up with the service adviser.

[DaveRuane]

I do know that Mobil 1 Synthetic grease is a cherry-purple color, and that Mobil 1 is a GM vendor. I wonder if it is that?

[BradL]

Spoke with my service adviser yesterday evening, and asked for the part # for the grease and he said there wasn't one, that it was not for sale yet. He did offer to "locate" some for me, but said I couldn't buy it. Bummer.

[Kent Tuttle]

"My friend is a mechanic at our local Chevy dealership. He told me he replaced a part in the drive line. It costs over a $100.00 just for the part. The new design is much better and removes the clunk. He told me, he will give me a copy of the bulletin that is now out for our trucks"

Any news on this bulletin?

[EIS01]

Sorry, I have not been around the computer much lately and forgot about it. I will talk to my friend and see if he can produce something for us. Have a great day, Kevin

[dmaxster]

A buddy of mine also works for GM and he said too that they are replacing the yokes with nickle plated and he has said it works.....I'm going to find out about the red lube....dmaxster

[Derek M]

ttt

[Derek M]

Any word on a bullentin/TSB for this issue yet? I have no recourse with my 2 piece shaft because it's a long bed crew cab.

[Jimamatic]

Derek M...
Look at a post I made on 07-01-02 page 4 titled,
Does anyone remember the surge? That should help.

[Derek M]

Jimamatic,

Looking at your post and the TSB summary you posted...

#01-04-17-004 drive axles, rear-clunk,bump,or
squawk noise.
Conditon

Some customers may comment on a clunk, bump or squawk noise when the vehicle comes to a stop or
when accelerating from a complete stop.

Cause

A slip/stick condition between the transfer case
output shaft and the drive shaft slip yoke may
cause this condition.

Correction

Replace the rear drive shaft slip yoke with a new
nickle plated slip yoke etc......
--------------

Seems this wouldn't apply with my truck as I don't have a transfer case (2wd). :(

[Jimamatic]

Derek M,
Bulletin 01-04-17-004 covers models 1999-2002
Chevrolet and GMC extended cab short box pickup
models (Silverado and Sierra) with 4L60-E (RPO M30)or 4L80-E(RPO MT1) automatic transmission and automatic 4WD (RPONP8). Kind of confusing I know.
I'm not even sure if my truck falls under this
bulletin.

[JEBar]

Had a drive line clunk in my 3500 CC when taking off from a standing start .... turned out to be a lack of grease in the connection between the two drive shafts ... dealer filled yoke with grease and have been clunk free for over 2,000 miles :cool:

[DaveRuane]

Mine is gone with no action on my part. Could some miles have broke in the spline? Truck runs great with one-piece and Trans SW update...