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Discussion Starter #1
I got a new differential...the one with the 15XXXXXX something. I got rid of my whine, but the clunck is still king kong loud! They checked the bushings and claimed they were fine. Am I suppose to be getting a clunck even with the new differential?
 

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2017 Camaro ZL1; 2011 CTS-V sedan; 2004 Lightning
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Start by torquing down your cradle bolts. As I recall, the GM specs have them torqued at only 90 ft/lbs.
 

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Owned 3 V's, now driving a Wrangler and XT5
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I thought I read from others that the parade clunk was gone.
 

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Alexandria, Va
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A "king kong loud clunk" sounds like there is a problem. I agree with lawfive - check your rear cradle bolts first. The front bolts should be tightened to 195 lb-ft and the rear bolts should be tightened to 141 lb-ft. These bolts don't have to be loosened to replace the differential, but anything is possible. Only other thing I can think of is maybe one of the differential mounting bolts (there are three; one in front and two at the back of the differential) is loose. If the front one is loose that will create all kinds of clunking/banging.
 

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2017 Camaro ZL1; 2011 CTS-V sedan; 2004 Lightning
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Lindsay Cadillac said:
A "king kong loud clunk" sounds like there is a problem. I agree with lawfive - check your rear cradle bolts first. The front bolts should be tightened to 195 lb-ft and the rear bolts should be tightened to 141 lb-ft. These bolts don't have to be loosened to replace the differential, but anything is possible. Only other thing I can think of is maybe one of the differential mounting bolts (there are three; one in front and two at the back of the differential) is loose. If the front one is loose that will create all kinds of clunking/banging.
James: what should THOSE bolts be tightened to? Thanks!

BTW: The 90 ft/lb number came from the Specter Werks instructions, not GM specs (sorry). Either way, though, not tight enough!
 

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Discussion Starter #7
I just got back and had them check the bolts to make sure they were tightened. The service tech...an old man...came out in a grumpy mood and claimed everything was ok with the car. My service rep was out for the day and so I had to deal with someone else. Anyways, we went for a test drive and I showed to the service rep the clunks. He claimed they were coming from the tranny and were all normal characteristics of the car. I noticed today that as my rpm's in 2nd and 3rd gear hit towards 3500-4500 rpm...the tranny started to make weird noises (like rattling plates almost). Also the clunking was clearly visible and they claimed it was a normal characteristic, regardless of if it came from the tranny of the rear. Too bad the service rep could not drive stick worth anything. I swear, even if my bolts were tightened, the way he drove it...it for sure became loose now. The guy was shifting all weird from 1-2nd and made noises I had never even heard in my life! Downshifting in ridiculous manners, no rev matching...and all this when I told him...the car makes the most noises when its driven slowly! Yeah...shifting at 5000 rpm and downshifting by jus riding out the clutch to 4000 rpm is not easy driving! And they said, I drive the car rough!!!!!!

Question is, why do I still have the cluncking and so many noises from my transmission? Lindsay, any suggestions? What can I do myself to fix these things? I swear I want to close down every damn dealership here in southern california! The service rep claimed all manual trannys made noises and had difficulty shifting...and it was funny to have my friend bring my corvette and prove to him that it had nowhere as many noises as the v-series. I still have a clunk and now my tranny makes a weird noise...any solutions?
 

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Alexandria, Va
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Ishminder,

It's hard to tell what's going on without being able to look at the car. The clunking could be loose cradle bolts or the front differential bushing. The rattling from the transmission sounds like an internal transmission problem. The transmission does make noise but I haven't heard a noise like that inside the car as you drive.

I wish I could be more help, maybe give another dealer a call and see if they'll look at it...
 
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