[invinceable99]

Hi all! So just upgraded my 05 CTS V to the LS7 clutch because the dual mass flywheel was causing some crazy vibrations.
The car runs very smooth, all went well, however now the car seems to make more noise now from about 2500 rpms and above. It sounds like the car has headers now!
Here is a link to a short video I recorded of some accelerating and perfectly highlights the sound:
https://vimeo.com/274087349
While it’s not super bothersome to me, I plan to ride share and wondering if this additional “noise” is normal for an LS7 clutch and flywheel conversion? The parts I installed are:
LS7 clutch, flywheel, pressure plate, slave cylinder and pilot bearing. LUK brand
ARP flywheel and pressure plate bolts
Tick performance remote bleeder.
Can anyone confirm that the LS7 clutch makes the V sound like this?
I did some searching and some people report some additional noise while others say no change in the noise department.
Thanks in advance for any help!

 

[darkman]

Was any part of the exhaust diassembled/reassembled during the clutch install? It sounds like an exhaust leak to me. The service manual procedure for a clutch change indicates removing the exhaust system.

 

[invinceable99]

Was any part of the exhaust diassembled/reassembled during the clutch install? It sounds like an exhaust leak to me. The service manual procedure for a clutch change indicates removing the exhaust system.

That's what I'm thinking but everything is tightened down, and I don't hear a leak when I'm under the car. I did take the cats all the way to the back, out but assembled everything properly.
Are there gaskets between the converters and headers? I didn't see any when I took them out.

 

[darkman]

There is a seal between the catalytic converter and the exhaust manifold, which the service manual indicates is non-reuseable. Rock Auto shows it as OEM part number 24505057.

 

[invinceable99]

There is a seal between the catalytic converter and the exhaust manifold, which the service manual indicates is non-reuseable. Rock Auto shows it as OEM part number 24505057.

Awesome, thanks Darkman! Going to dismantle the exhaust and make sure the gaskets are intact. Also installing new starter wire and starter wrap because I busted that wire when installing the clutch. Can't believe GM didn't wrap the starter from the factory seeing how close it is to the exhaust.

 

[89eldorado]

Yea if its a high pitched ticking then the donut seals after the cats are the problem. If you go to AutoZone, they have them, they are the same as the ~2005 corvette's, they wont be able to find them under cts-v parts...

 

[kbraniff]

hmmmm… Clutch noise... I have one I'm trying to diagnose. I had a stock clutch (supposedly ordered from Cadillac/GM) installed by a trans shop about six months after I bought the ol' V1 (that makes it around about summer 2015). About three months after the install I noticed a rattling or chortling sound when I shut down the engine. It occurs whether the pedal is fully depressed or fully out. If I am releasing the pedal as I shut down the engine there is no noise. Otherwise the clutch feels fine and the trans shifts fine. No problems other than the noise. I attempted to get a diagnosis from the Chevy dealer I go to but the mechanic couldn't determine anything other than the noise is coming from the clutch/flywheel area. He recommended that if everything functions fine just let it be. Good advice? Or am I heading for a serious problem?

 

[89eldorado]

I would let it be as I am from the school of "If it aint broke dont fix it." But actually it sounds like a motor mount to me... I have medium-hard poly mounts and mine rattles like a diesel everytime I turn it off.

 

[kbraniff]

I would let it be as I am from the school of "If it aint broke don't fix it." But actually it sounds like a motor mount to me... I have medium-hard poly mounts and mine rattles like a diesel every time I turn it off.

I already got the Creative Steel mounts. Originals were totally blown apart. Hopefully they are in there correctly... But if this is the case why would the noise not be present when releasing the clutch while shutting down the engine? Actually that is weird for whatever the problem could be...

ADDITIONAL INFO: You could be onto something 89eldorado... The engine mounts were installed somewhere around the end of February 2016 (exact date not determined due to conflicting dates on dealer repair order and invoice for mounts). The first inspection for the "rattle" was 3/9/2016 but this was in conjunction with two codes related to the bank one O2 sensor. Sensor was replaced and the mechanic believed the rattle was gone so the rattle had to be from the faulty sensor. (Yeah I had questions about that too... Do O2 sensors rattle when they go bad?) Rattle was checked again on 5/24/2016. This time the mechanic believed the rattle was coming from the transmission/clutch area. So... The rattle did present shortly after the mounts were installed. I never crawled under the car myself to try to determine where and under what conditions the rattle presents. Now I'm about 99% sure the noise is not related to the clutch. Considering I picked up the car from the clutch repair on 7/3/2015 and the noise presented around late February or early March 2016 that is a long time in between... Since the clutch and transmission operate fine I'd guess nothing in there is broken, worn or otherwise defective. Had it been an installation error I'd guess it would have presented long before this. Maybe it is related to the mounts...

 

[89eldorado]

"But if this is the case why would the noise not be present when releasing the clutch while shutting down the engine? "

That is an odd operation to do. But anyway, adding drag to the rotating engine (which is slowing) would provide a dampening effect similar to what a soft or stock engine mount would provide.

It is not really possible to mess up installing engine mounts. I guess something could be not torqued down and thus loosen up over time, which would be present also when you hit bumps going down the road.

 

[kbraniff]

"But if this is the case why would the noise not be present when releasing the clutch while shutting down the engine? "

That is an odd operation to do. But anyway, adding drag to the rotating engine (which is slowing) would provide a dampening effect similar to what a soft or stock engine mount would provide.

It is not really possible to mess up installing engine mounts. I guess something could be not torqued down and thus loosen up over time, which would be present also when you hit bumps going down the road.

This is making sense now. When I was talking about the "installation error" I didn't clarify that I meant the clutch. But maybe it could be an installation error on the mounts. I was beginning to think this was a "loosen up over time" issue but the noise started just days after installation. I just had another thought... When I picked up the car after the installation of the mounts the service manager started to say something about the heat shields for the mounts but he didn't finish the thought. Anyway... Speculation won't do anything for the problem. Next service visit I'll have them recheck the mounts.

 

[Billfrombyron]

It shouldn't diesel with poly mounts at all.

When mine did, it is because I had melted the CS black mounts. You absolutely could not tell installed, I just happened to score a deal on a set of UMI mounts and was swapping them to try them out.

I never suspected the mounts at all, until they were removed to install the new ones.

-Byron

 

[kbraniff]

It shouldn't diesel with poly mounts at all.

When mine did, it is because I had melted the CS black mounts. You absolutely could not tell installed, I just happened to score a deal on a set of UMI mounts and was swapping them to try them out.

I never suspected the mounts at all, until they were removed to install the new ones.

-Byron

Wait... Did you say the CS mounts melted? In my last post I recalled that... When I picked up the car after the installation of the mounts the service manager started to say something about the heat shields for the mounts but he didn't finish the thought. I hope this didn't happen. But that would have been pretty quick to fail. The noise started in about a week's time after installation.

 

[invinceable99]

Just an update:
Replaced all the gaskets on both sides of the catalytic converter, and made sure everything is tightened down and the V is still sounding like it has headers and yet it doesn't.
The sound is far mode pronounced when the car is in gear and more than 20% throttle is applied (although its slightly audible when revving at idle). It also seems to come from the rear of transmission/front driveshaft area.

 

[kbraniff]

Just an update:
Replaced all the gaskets on both sides of the catalytic converter, and made sure everything is tightened down and the V is still sounding like it has headers and yet it doesn't.
The sound is far mode pronounced when the car is in gear and more than 20% throttle is applied (although its slightly audible when revving at idle). It also seems to come from the rear of transmission/front driveshaft area.

Hmmm... Sounds like a few problems I had based upon the location you discovered. When I was on the test drive there was a severe "clunk" sound seemingly coming from the far rear; I imagine it was between the rear of the driveshaft and the differential. The dealer claimed to have replaced the u-joint and diff input seal. Later I learned the trans was leaking from the tail shaft housing. Also, there was still a bit of this "clunk" sound. I took the car to a trans shop and they found the housing was loose. They replaced the seal and re-installed the housing. Now, granted, a "clunk" sound and a "header" sound are different but given the location it could be worth a look.

 

[Billfrombyron]

It shouldn't diesel with poly mounts at all.

When mine did, it is because I had melted the CS black mounts. You absolutely could not tell installed, I just happened to score a deal on a set of UMI mounts and was swapping them to try them out.

I never suspected the mounts at all, until they were removed to install the new ones.

-Byron

Wait... Did you say the CS mounts melted? In my last post I recalled that... When I picked up the car after the installation of the mounts the service manager started to say something about the heat shields for the mounts but he didn't finish the thought. I hope this didn't happen. But that would have been pretty quick to fail. The noise started in about a week's time after installation.

Yep they melted.

https://byronsworld.smugmug.com/2006-Cadillac-CTS-V/n-9tr9v2/i-w9K8Jfh

-Byron

 

[kbraniff]

Yep they melted.

https://byronsworld.smugmug.com/2006-Cadillac-CTS-V/n-9tr9v2/i-w9K8Jfh

-Byron

Great... So what was your remedy? How did you fix this problem?

 

[Billfrombyron]

Yep they melted.

https://byronsworld.smugmug.com/2006-Cadillac-CTS-V/n-9tr9v2/i-w9K8Jfh

-Byron

Great... So what was your remedy? How did you fix this problem?

I didn't know they had melted. You absolutely could not tell while they were installed other than crazy vibes.

I had scored some UMI mounts, and wanted to try them out while the clutch was being changed out for an ACT twin.

Love the UMI mounts, totally vibe free and the car feels amazingly hooked up and much more solid.

It wasn't until the mounts came out that it was noticed.

I was chasing a crazy vibe and that ended up being the root cause. The UMI mounts are smoother in my car than the CS black mounts were.

-Byron

 

[invinceable99]

Last update and solution!
So I finally figured it might be my Creative Steel transmission mount and decided to get under my car and change it out to a new factory mount that I had purchased a while back. I installed the mount a few days ago and all the noise is gone!
I didn’t take pictures of the old mount but below is the Creative Steel mount.

As you can see, it’s quite tall when compared to the factory mount(maybe .5-1” taller), and mine has a weird “hump” in the middle which pushed the transmission to close to the tunnel and caused all the vibrations and rattling in the cabin.
I didn’t want to think an “upgrade” would make something worse but in this case, this mount was either not manufactured correctly or just not right for my car.
Now my V drives quietly and beautifully as it should, and I can really feel and hear the difference moving from the dual mass flywheel and clutch to the LS7’s clutch and flywheel setup! The dual mass flywheel on mine was vibrating severely and this was a nice upgrade and solution.
I know solutions don’t get posted often, but hope this helps someone in the future!
Thanks for all the help everyone!

 

[Billfrombyron]

Last update and solution!
So I finally figured it might be my Creative Steel transmission mount and decided to get under my car and change it out to a new factory mount that I had purchased a while back. I installed the mount a few days ago and all the noise is gone!
I didn’t take pictures of the old mount but below is the Creative Steel mount.
View attachment 583947 As you can see, it’s quite tall when compared to the factory mount(maybe .5-1” taller), and mine has a weird “hump” in the middle which pushed the transmission to close to the tunnel and caused all the vibrations and rattling in the cabin.
I didn’t want to think an “upgrade” would make something worse but in this case, this mount was either not manufactured correctly or just not right for my car.
Now my V drives quietly and beautifully as it should, and I can really feel and hear the difference moving from the dual mass flywheel and clutch to the LS7’s clutch and flywheel setup! The dual mass flywheel on mine was vibrating severely and this was a nice upgrade and solution.
I know solutions don’t get posted often, but hope this helps someone in the future!
Thanks for all the help everyone!

That is the old style CS mount, and yep it was too tall on my car also.

I run their new style and it's fantastic. It is the same height as the stock mount with revshift insert, which is the perfect height and angle for my car.

-Byron