Rear Diff Clunk Dealer Refused to Fix

[JDAM]

Took my 2004 Sierra SLT Crew Cab Z71 4X4 in to dealer for clunk in rear end when accelerating from a stop.

The 2 year old truck still under warranty has only has 12500K noise developed about 11000K.

The dealer inspected the rear diff, lubed the rear spring insulator, and stated that everything was within specs. The clunk is still there.

 

I searched the forum and found a link to TSB 01-04-17-00B Jan 05,2005

My I have the once piece drive shaft but my exact model (crew cab short box) is not listed in the TSB dated Jan 5, 2005. I read the TSB has been updated to include up to 05 models.

 

Is my dealer being lazy? Or am I wrong is there an acceptable clunk?

 

Also requested that rear diff service on my dime they didn’t perform that service either.

 

At least they stroked the steering shaft I got that problem too.

[StoneyPgh]

I think your first move should be to find another dealer.

Failing that, then a phone call to GM Customer Service.

[Jasonsupafly]

I 2nd that.. yep yep

[vctbmcam]

I have the same problem on my 05 GMC CC Z71. When starting from a stop you hear a loud clunk from the rear, drove me crazy. I had some people tell me that it was from the slip yoke. I first had it at the dealer around 15,000 with the problem and they said that there was nothing wrong, Lazy #*$ AZ dealers ( just in it sell aftermarket) don't give a darn. Now at 30,000 the clunk is driving me really crazy so I recently moved to TN and took it the dealer and told them about it poss. being the slip yoke.

 

The dealer said that the slip yoke was tight and that they performed (E5130 lubed rear springs and mounting points). have not heard the clunk yet. Hopefully If I keep it lubed they found the source.

 

I have seen alot of information about a clunk from the rear being the slip yoke and that GM will do anything because they say it is normal.

[I-H8-4Ds]

What about rear axle wrap on accel?

[JDAM]

Spoke with the dealer they are going to look at it again on the 22nd. I’m more frustrated with the dealer’s service department than the slip yoke issue. This is not the first time I’ve had to return more than once to get a repair done right. Before I became an engineer I worked on military aircraft for 23 years we didn’t get second chances. This is a small town dealer in southern Maryland, the only one around for 40 miles his claim to fame is that he is the second oldest Chevy dealer in the US.

 

As far axel wrap goes it’s my understanding that the yoke does not slide smoothly on the output shaft when the drive shaft is not rotating or rotating at lower RPMs. When you take off the axel wraps downward pulls the yoke away from the transfer case and gets stuck there when the yoke finally slips the clunk or bump is actually caused by the sudden release of tension on the rear leafs as the differential returns to it’s normal position. The axel wraps more on takeoff than acceleration when under speed plus the drive shaft is turning fast enough to keep the yoke from sticking this is why it only happens on take off.

 

If I’m not mistaken the output shaft on the transfer case is sealed the yoke and output shaft splines are dry eventually dirt and corrosion build up causing the yoke to stick

 

The 2WDs don’t have this issue because the output shaft is not sealed yoke and spline are splash lubricated.

 

I’m going to attempt to attach a PC camera to the rail and tape the yoke and rear diff will results post if successful

[onkyo]

I have had two 2001 silverados, a 2003 and now a 2004.....they all have the clunk in the rear. None of them have ever given me any problems but the first did concern me until I got another......then another......now another. Oh well.

[2005 GMC SIERRA]

I had a 2000 Chevy Z71 regular cab and now a 2005 GMC Z71 crew cab....they both have had this clunk. Not too loud but noticeable and for a nice truck, you would think they could fix that.

[itasca]

Is this "clunk" that you guys are talking about something more than the sound made by the Eaton locker when it locks up? Does it happen only when accelerating hard enough to slip a rear wheel?

[dogzapper]

My 2003 Silverado Z-71 EC/SB "clunked" often; mostly from startup, but also when I dropped in power and accellerated again (like slowing for a stoplight and it turns green again). My Chevy dealer's service is second to none and we never did find the problem. My service writer, who has been there forever told me that "The problem is common and that it apparently will not cause any longevity issues."

 

I sold the Z-71, not because of the "clunk" but because we needed a truck that would pull our travel trailer. It was killing me, pulling our Oregon mountain passes at over 5,000 RPMS on the great 5.3-liter engine. Eventually, either the engine or the transmission (a clueless bugger) was going to break.

 

Soooo, we bought a 2006 Silverado Duramax/Allison. The "clunk" is absolutely GONE.

 

Steve

[JDAM]

It's not the locker the clunk happens under during normal acceleration when starting from a stop. Sometimes it feels like a bump from the rear. It is caused by the slip yoke on the rear drive shaft. Like the steering clunk it’s more of annoyance than anything. The temporary fix is to remove the drive shaft and lube the yoke. GM has a replacement yoke that is nickel-plated it is suppose fix the problem TSB 01-04-17-004B

[GSXR_RCR]

Had the same problem when i bought a used 2000z71, took it back to the dealer(toyota) and they said it was fine. Mechanic at work found a tsb about the slip yoke, Went back waving it in their face(toyota that is) and demanded it to be fixed(gave me a 90 day 100% warranty). The shipped it next door to chevy and they fixed it. Then got a new rear window(leaking) and got the intermediate shaft fixed, new battery. I thought I worked that dealer over. Anyways its probably your slip yoke, some have said its easy to fix, but I never tried it. If its under warranty Try to find the TSB about it and go to the dealer and be a pain in the A$$. Make them acknolwdge it and fix it.

[pm26]

Does anybody know if 2006 and newer trucks have the upgraded nickel plated, closer tolerance rear yoke? I have not experienced any clunking on my 06 crew cab Z71 yet. but I have under 6k miles on the truck. I read somewhere that this issue is more common with extended cabs than with crew cabs.

[chevyhutch]

I have a 2006 ex-cab 4x4 and it's had the clunk since day one took it back they said it was normal (surprise ) lol it's like the other guy stated slowing down for a stop light and it turns green before you stop so you give it gas and shifts gears and pops big time. even slowing down when it gears down it will clunk. i'm going to take it back with the TSB that's been posted and see if they will fix it.

[WindyCityPilot]

I have a 2006 ex-cab 4x4 and it's had the clunk since day one took it back they said it was normal (surprise ) lol it's like the other guy stated slowing down for a stop light and it turns green before you stop so you give it gas and shifts gears and pops big time. even slowing down when it gears down it will clunk. i'm going to take it back with the TSB that's been posted and see if they will fix it.

 

Keep us posted what the outcome is. I have the clunk that happens when slowing down for a stop. I have not heard the clunk when accelerating....yet.