jackrmartz

Thank you in advance for any assistance anyone can bring to the table on my current issues. I am so frustrated I am willing to offer payment for a solution...... I have a 2005 V which I love dearly but cannot stand the clunk and odd excessive movement/clunk in the drive-train anymore. I have read all different variety of fixes and just plain confused. I contacted Luke at Lindsay Cadillac and he states they have noted the concern can be eliminated by changing out the clutch and flywheel with the c6 z06 design. Guys, I can handle the minor clunks and gear whine but now the drive-line almost feels like it is going to fall out when engaging and disengaging the clutch. I had it up on the rack and all seems to be good. The only visual concern I can see is the bushing that stabilizes the shifter rail are almost all the way out. Can this simple little thing cause this excessive clunking noise? I guess I am at my wits end with one thing after another. I am hoping and praying someone has gone through this and is willing to lend a hand.

history of car:

1) diff replaced with 2006/2007 type under warranty
2) diff bushing at the same time
3) bmr pinion plate
4) b&m shifter -
5) motor mounts have been replaced under warranty so many times i have lost count
6) i do not drive the car hard

Please help me guys........ and god bless the person that can help!!!!

Also, If I can help anyone with tire questions please do not hesitate to ask!!!!

rjoffe

In my experience there are a number of major factors that affect the clunk (there are many other minor ones):
- Motor Mounts
- Dual mass flywheel
- Driveshaft
- Diff bushing

The problem is that you can replace all of these with stock GM components and the clunk will be mostly gone. However it will come back. You don't say when your replaced all these parts.

My personal experience is replacing the motor mounts and diff bushings (under warranty with GM parts) at about 24K miles, by 34K miles most all of the clunk is back.

There are after market components that are much more robust then the GM stock parts. Luke can set you up with all of them, there are other vendors that have parts as well.

I would venture to guess that a replacement of the motor mounts, diff bushing, and two piece flywheel with robust after market parts will eliminate most of the clunk. Your driveshaft may also be a cause, as that coupling may cause some clunk if worn.

Even with all replacement parts the entire system will have some clunk, it's a result of the compromises made when the V was designed.

just my 2c

Ron

jackrmartz

Ron,

I greatly appreciate your advice and the time you took to respond to my post. You are absolutely correct I can replace the parts with factory Gm but the problem returns over and over again. I guess I am just desperate to fix the car and just enjoy it. If you were doing this all over again with all the knowledge you have now, where would you start? Could you list the order of what you feel would be the right way to attack this problem? I learned to accept the clunk when I initially purchased it @ approx. 32k miles but now almost @ 60k it has progressively gotten worse to a point one day it just felt wrong. I performed a visual inspection and could not find anything broken or abnormal other than those bushings which are located at the shifter base that always look like they are slipping off the rods which I believe UUC sells replacements for in urethane. Can these bushings cause this kind of noise and feeling above the normal clunking? Or is the combination of the flywheel @ 60k, and as you stated earlier, other concerns all contributing to my problem. Again any guidance is greatly appreciated!!!!!

Thank you kindly,

Jack

jackrmartz

Ron,

I just re-read your response and noted your statement on the drive-shaft. What am I looking for with regards to a problem? What key area do I need to focus on? Do I just replace it with an aftermarket one piece made out of aluminum or carbon fiber? What is your suggestion on diagnosing a bad driveshaft?

Thanks again for all your time in this matter!!!

Jack

rjoffe

1st, where are you located?

2nd how much of the work can you do yourself?

3rd how much cash do you want to burn?

-T-

iTrader: (2)

In my experience and understanding, the clunk is due the the soft materials used to give that "cadillac" ride as much as they could while still being firm enough for performance. The main contributors to the clunk are:

-Motor mounts
-Transmission mounts
-Flywheel
-Differential bushing.

The bushings you see that are "halfway out of place", shouldn't cause much clunk. Those bushings are for your shifter linkages. Replacing those would take the "sloppiness" out of the shifter though.

Getting harder after market motor mounts, filling your transmission mount with a poly as a few on here have done will help out. If you look at maxspeed96ct's thread https://ls1tech.com/forums/cadillac-...rts-sedan.html you can see how bad our stock dual mass flywheel is.

I am not saying that it is impossible, but i doubt the driveshaft itself is causing that much clunk. Next time you have it on a lift, set the e-brake and put the transmission in 1st gear. Attempt to rotate the driveshaft by hand to see if there is any play, clockwise and counter-clockwise.

And as rjoffe stated, the irritating issues owners have with these cars are due to compromises GM made to have a cadillac performance vehicle. When you tighten all that clunk and softness up, you will feel like your in an 11 second Trans AM instead of a Cadillac.

jackrmartz

Hi and thanks in advance for any help you can bring to the table.... I greatly appreciate it....

1) I am located in Ventura County, CA

2) I can do all the work myself.....

3) I do not want to burn cash but I understand I will need to spend money,
just want to spend it wisely on mods that work.

Thanks again

Jack

jackrmartz

Hi T,

Thanks in advance for your help and time.

I hope I am correct in making this statement, it appears there is some form of a trend with regards to the flywheel design which after high mileage can cause my specific sensation, "excessive driveline movement felt and/or clunk noted while engaging or disengaging the clutch at slow speeds between 2-15 mph" and or "shifting between 1st and second or just coming to a stop and proceeding forward again. It just seems very odd, almost as if the tranny mount is broken and allowing all that driveline movement. Maybe it is indeed the high mileage clutch and flywheel!

T, Where do you think I should begin?

Thanks

Jack

-T-

iTrader: (2)

If it bothered me as much as it seems to bother you, i would purchase a set UUC motor mounts for a "softer" mount. Otherwise search the forums for a set of manufactured mounts. Purchase an upgraded clutch flywheel kit of your choice. Follow MightyMouse's poly fill procudure for the transmision mount.

Relative costs

Motor Mounts - 350
Poly for Tranny mount - 50
ZO6 clutch upgrade - 995 from corvettedoctor.com

For roughly 1400 and some of your own time to install everything, you will get rid of 90% of that clunk. Although, you will feel a rougher idle and more vibration from stiffening the mounts. Your gear changes and 2nd gear releases from a roll will improve greatly.

You might want to contact maxspeed96ct and speak to him personally. He seems very happy with the improvements he has made. He could tell you more of what he was unhappy with, and the pros and cons of his mods.

rjoffe

I would just add that you probably should replace your diff bushing as well. Either get a UUC one from Luke, or I think some others have started making those as well.

T added it in the price list, but didn't include in his description.

There is a diff removal bushing floating around that will help removing the old one. contact pisnuoff on the other forum.

scatillac

iTrader: (12)

Another clutch alternative is GM part number 12570806, which is a factory balanced assembly (a clutch cover, disc and flywheel). This, along with either a Katech or TPIS clutch slave spacer will do the trick.

If you're on good terms with a GM parts man, this setup can be had for ~$575. The spacers run about ~$85 from either supplier. You'll save at least $300 over the C6 Z06 clutch stuff.

This is what's in my car (behind a very mild LS7...504 rwhp/491 rwtq) since Sept 07 and it's doing fine. Unless you're a drag racer or just hammer the living crap out of it, you'll be fine.

If your current engine mounts are still good, a torque limiting cable (3/16" or 1/4" Inox) on the driver's side will end your motor mount issues without causing any vibration. You leave enough slack (about 1/2") to allow normal engine movement but not enough to allow the mount to be under enough tension to separate. This has also been on my car since Sept 07.

I bought a really good set of mounts but haven't installed them yet because the cable is still working and I'm lazy to pull the headers. I'll probably wait until I change the cam (still undecided) to do it. I would either replace or urethane fill the rear mount though.

-T-

iTrader: (2)

I will have to write that setup down.

On the other hand. I unbolted my motor mounts and dropped my sub frame last night. I dont think you would have to remove your headers to get the motor mounts out. Although i have stock manifolds and havent seen the clearance issues that headers on our engine bays have. Just food for thought!

maxspeed96ct

iTrader: (3)

I have polly motor mounts, trans mount and diff bushing with single mass steel flywheel with a spec 3 clutch..

No more major clunk , car feels very solid and sporty....but I do sometimes get a some small noises as and RWD manual trans would ..
(I think the drivesaft has something to do with it to )

If your looking for a clutch upgrade but want ride comfort, go with a LS7 clutch kit with a single mass steel flywheel..


If you drive hard go with a spec or a monster

After upgrading my clutch I got rid of the rattle I used to get a shut down. check my other thread to see how bad my flywheel was .

jackrmartz

All you guys who took the time to help me, thank you from the bottom of my heart. You have all given me hope! If I can assist please do not hesitate to ask. I am in the automotive business and run a tire store in West LA. So here is what I am thinking I should do. Please review and chime in on any suggestions. Just more info, I commute 90 miles a day!!!

1) per "T" set the e-brake and put the transmission in 1st gear. Attempt to rotate the driveshaft by hand to see if there is any play, clockwise and counter-clockwise to verify my driveshaft is ok and does not need replacement. ***** Is this correct process for checking *****

2) per "scatillac" If your current engine mounts are still good, a torque limiting cable (3/16" or 1/4" Inox) on the driver's side will end your motor mount issues without causing any vibration. You leave enough slack (about 1/2") to allow normal engine movement but not enough to allow the mount to be under enough tension to separate. ***** what is the best way to verify condition of ones motor mount if a visual inspection yields no leak. ******

2b) ****** or do I just replace the mounts, engine and transmission with
the ones everybody seems to be commenting on, not the "UUC."
****** or just the motor mounts and utilize this poly stuff for the
transmission mount?


3) per "scatillac" Another clutch alternative is GM part number 12570806, which is a factory balanced assembly (a clutch cover, disc and flywheel). This, along with either a Katech or TPIS clutch slave spacer will do the trick.

****** Is pn# 12570806 a c6 ls7 designed clutch similar to the more expensive corvette doctor package z06 clutch kit*****

4) per "T" Poly for Tranny mount instead of a new urethane mount?

5) per "maxspeed96ct" he has polly motor mounts, trans mount and diff bushing with single mass steel flywheel with a spec 3 clutch.....
****** so not to sound redundant but which polly style is the best and is appears get the diff bushing from Luke.

6) Where do I find this so called tool to allow for easy removal of the bushing, or a common-man way to replace the bushing?

So, based on what I have written above this should eliminate that annoying concern I have when engaging and disengaging the clutch while driving at low speeds while utilizing 1st and 2nd gear....

Again, thanks for all your help, please do not hesitate to ask for my help if need be.

I will keep everyone posted with my situation and if no one adds anything further than I will proceed as outlined....

Thanks to all!!

Jack

scatillac

iTrader: (12)

No leaks and no excess vibration (especially on engine turn-off).

As far as aftermarket mounts, the mounts that I purchased for future installation are by 2003RC51. IMHO they are the class act of the field but due to their design, will probably have a bit more felt vibration than the others. That, however, is not an issue with me, as their construction and design is, well...just the best.

The 12570806 package was for originally for C5 LS6 Corvettes and was also used in the LS1 GTOs. It's a flat single-mass flywheel (around 25 lbs) instead of having the offset clutch mounts used on the LS7.

Most GM clutches are made by LUK/Exedy so it's also available on the aftermarket. I put the aftermarket one in my truck and it even had a GM part number on it.

This unit is plenty strong for our CTS-V application except for the drag racers and guys who do a lot of clutch dumps with sticky tires. Like I said, it has held up behind my LS7 (which makes more torque at 2000 rpm than a stock LS6 or LS2 does at peak) very well for 2 years. I've also got 275/40 PS2s on the rear to further complicate things for any clutch.

jackrmartz

Hi Carl,

Thanks again for your response.

Per your quote: The 12570806 package was for originally for C5 LS6 Corvettes and was also used in the LS1 GTOs. It's a flat single-mass flywheel (around 25 lbs) instead of having the offset clutch mounts used on the LS7.

It appears the Gm clutch kit would be the best choice based on my situation. Based on your quote " instead of having the offset clutch mounts used on the LS7,"
Does this mean the clutch kit will require a different slave cylinder or just the spacer? If so, who is the best source of the spacer.
Per your motor mount suggestion with regards to the motor mount, who sells it? Is is a stock replacement, liquid filled or a urethane?

Last but not least, Where do I find this so called tool to allow for easy removal of the bushing, or a common-man way to replace the bushing?

Happy holidays, and Thanks again,

Jack

scatillac

iTrader: (12)

Both the LS7 & C5 clutches require a spacer. You don't need to change the slave cylinder unless you want to spend the extra money. Either the TPIS or Katech spacers will work. Replace the fluid (DOT3) with a high-quality, high-temperature fluid when you do the clutch, manually back-bleed it and you're all set.

2003RC51 makes the motor mount that I was referencing. It's urethane, but it's a different style mount (much stronger) from the one's you normally see for our application. Do a search on his posts and you'll see them. Absolutely top-notch workmanship!