: 2100-2350RPM Vibration fix is eluding me



DougNuts
06-21-11, 06:47 PM
I have an '04 V with 71K on it. Since I bought it (65k) it has had a vibration at 2100-2350RPM in any gear (accelerating and decelerating) and a shudder at shutdown.

I have installed CS motor mounts, LS7 flywheel and an ATI damper and the issue still persists.

Has anyone been successful in eliminating this vibration? It has to be the engine, so what is it?

Houdini
06-21-11, 06:55 PM
What about out of gear and rev the engine to the same rpm... get vibration then?

DougNuts
06-21-11, 08:47 PM
What about out of gear and rev the engine to the same rpm... get vibration then?

I don't think so, but I've only tried it one or two times.

CadzillaTN
06-21-11, 09:53 PM
V is for Vibration

Houdini
06-22-11, 08:24 AM
^hahahahah

DougNuts
06-22-11, 08:37 AM
What about out of gear and rev the engine to the same rpm... get vibration then?

When I rev it in neutral, it does a similar vibration at a all RPMs up to 3k (highest I took it), so I can't tell any difference at the RPM range that I've been talking about.

lollygagger8
06-22-11, 11:08 AM
Try reindexing your driveshaft. You always want to mark where it sits before you remove it.

CadzillaTN
06-22-11, 02:35 PM
The driveshaft doesn't spin if the car is stationary and in neutral, correct?

lollygagger8
06-22-11, 04:52 PM
The driveshaft doesn't spin if the car is stationary and in neutral, correct?

Correct.



My guess is it is the LS7 flywheel. Everytime someone gets rid of the dual mass turd they complain about that rpm range giving vibes. Mine does it too (Monster 14 lb fw/stage 3 clutch) I've gotten so used to it, I think it's normal.

DougNuts
06-22-11, 08:49 PM
Try reindexing your driveshaft. You always want to mark where it sits before you remove it.

I've thought about it, but I've never heard of a driveshaft issue occurring in 6 different gears at the same RPM. Driveshaft issues typically occur in relation to vehicle speed (i.e. driveshaft speed).


My guess is it is the LS7 flywheel. Everytime someone gets rid of the dual mass turd they complain about that rpm range giving vibes. Mine does it too (Monster 14 lb fw/stage 3 clutch) I've gotten so used to it, I think it's normal.

I had the same issue before I did anything to the car. I've spent $2000 fixing what are three common failure modes on our cars and now I'm left scratching my head. I don't see how it could be anything after the transmission input shaft. That only leaves the tune or balance of the engine...

Skidmarcx
06-23-11, 12:17 AM
I agree on the flywheel... if it's an RPM thing then it makes sense

DougNuts
06-23-11, 12:32 AM
I agree on the flywheel... if it's an RPM thing then it makes sense

Again, the car did it with the stock flywheel and with the LS7 flywheel.

silver02stang
06-23-11, 01:14 AM
Correct.



My guess is it is the LS7 flywheel. Everytime someone gets rid of the dual mass turd they complain about that rpm range giving vibes. Mine does it too (Monster 14 lb fw/stage 3 clutch) I've gotten so used to it, I think it's normal.

I noticed the same thing when I went to a Monster STG II w/ lwfw.... I'd be curious to see if an ATI dampner added the same time this clutch swap is done would address the vibes.

darkman
06-23-11, 08:08 AM
Again, the car did it with the stock flywheel and with the LS7 flywheel.

When you installed the LS7 flywheel, did you install a new clutch disc and pressure plate at the same time?

DougNuts
06-23-11, 09:00 AM
When you installed the LS7 flywheel, did you install a new clutch disc and pressure plate at the same time?

Of course, LS7 slave cylinder too.

darkman
06-23-11, 09:33 AM
Of course, LS7 slave cylinder too.

Okay. If I have read the previous posts correctly, the vibration is present when the car is parked, in neutral, with the clutch pedal either up or down. Additionally, the vibration existed before the new harmonic balancer and before the LS7 clutch system. If all that is correct, it suggests a vibration unrelated to the engine itself (handled by the balancer) or the clutch (although the track record of LS7 setups with regard to vibration is less than stellar). The next logical source would seem to be the engine-driven accessories which includes those devices driven by the serpentine belt (power steering, AC, water pump and idler pulleys). To test that, one simply removes the serpentine belt to see whether the vibration remains with no belt driven devices at play. Obviously, you don't run the motor very long without the belt.

lollygagger8
06-23-11, 09:56 AM
I've thought about it, but I've never heard of a driveshaft issue occurring in 6 different gears at the same RPM. Driveshaft issues typically occur in relation to vehicle speed (i.e. driveshaft speed).

Tires?

Maybe your carrier bearing in your driveshaft is shot?

I'm still guessing it's connected to the flywheel/clutch though.




Okay. If I have read the previous posts correctly, the vibration is present when the car is parked, in neutral, with the clutch pedal either up or down. Additionally, the vibration existed before the new harmonic balancer and before the LS7 clutch system. If all that is correct, it suggests a vibration unrelated to the engine itself (handled by the balancer) or the clutch (although the track record of LS7 setups with regard to vibration is less than stellar). The next logical source would seem to be the engine-driven accessories which includes those devices driven by the serpentine belt (power steering, AC, water pump and idler pulleys). To test that, one simply removes the serpentine belt to see whether the vibration remains with no belt driven devices at play. Obviously, you don't run the motor very long without the belt.

^definitely worth a try^

AG'S-V
07-28-11, 10:42 AM
Bumping this thread...I'm in the EXACT same boat.

My buddy that helped me put my LS7 clutch in is a GM tech...so I'm going to lean on him for a possible solution.

DougNuts
07-28-11, 11:50 AM
AG'S-V, let me know what he says. Like you, I have contemplated selling the car after dropping $2000 into it and still having the same vibration.

I would try to run the car without the accessory belt, but it's most noticeable (read: easier to hold it at the right RPM) in higher gears and I don't want to drive it that fast/long without the belt on.

AG'S-V
07-28-11, 12:01 PM
After doing research on other LS forums it appears that I need to have the flywheel, disc and pressure plate all balanced seperately...then together as a whole to be verified.

Nothing to do with accessory drives...it was smooth as silk with the OEM clutch on mine.

And yes...I thought about selling mine too...new 5.0 Stang is looking reeeaaaally good about now :)

AG'S-V
07-28-11, 05:21 PM
UPDATE

Taking it in on Monday to have the clutch pulled, balanced and put back in...Tech Auto in Houston quoted me $323 to take it out, $70 to balance and put it back in...not bad!

Will report back next week.

DougNuts
07-28-11, 08:11 PM
UPDATE

Taking it in on Monday to have the clutch pulled, balanced and put back in...Tech Auto in Houston quoted me $323 to take it out, $70 to balance and put it back in...not bad!

Will report back next week.

Sweet deal, let me know how it goes. I wouldn't hold my breath if I were you though, my car did it with 100% stock parts and 100% LS7 parts. I do not think it's the issue on my car. I am wondering about my input shaft on the transmission though.

67electro
08-02-11, 12:16 PM
if you put the car in gear, but keep the clutch in (car not moving) then the input shaft as well as the clutch disk will not be moving. the only thing rotating will be the engine, flywheel and pressure plate.

this will rule out anything to do with the transmission & drive shaft. drive shaft only moves when the car does.

67electro
08-02-11, 12:19 PM
I really hope you both figure out whats going on. I just put Ultra mounts in, and I have the vibes too. I was sure it was the flywheel becuase I too had the shudder at shutdown, I am at 104k and in hot Phoenix.

reading this post : http://www.cadillacforums.com/forums/2004-2007-cadillac-cts-v-general/226438-dual-mass-flywheel-gone-bad-caused.html#post2549475

I was like "Woohoo!" all I need is a new Flywheel/clutch setup. but with you two (DougNuts, and AG'S-V) now I am worried.

AG'S-V
08-02-11, 12:54 PM
I get the car back today...fingers crossed!

Seems some of the Vette guys had the same issue...shop I'm using is familiar with the issues too, he's confident this will take care of it.

67electro
08-03-11, 12:37 PM
@AG'S-V - how did it go?

AG'S-V
08-03-11, 03:00 PM
FIXED!

Car is smooth as silk now through all the RPM range, shifting has improved too...it's not "tight" anymore and back to normal.

http://i236.photobucket.com/albums/ff266/jetch17/GIFs/ev0z9d.gif

DougNuts
08-03-11, 03:17 PM
That's great! I don't understand how my stock flywheel and the LS7 flywheel would both cause the exact same vibration....

67electro
08-03-11, 03:31 PM
@AG'S-V That is very cool.

so now you are running an LS7 Flywheel, Clutch, Pressure Plate, and Slave, with smooth results..
what motor mounts do you have? Stock? or CS Ultra?

AG'S-V
08-03-11, 04:13 PM
CS motor mounts and tranny mount, as well as their rear end bushing/block.

It went from almost feeling like a cylinder was missing at 1800ish rpm to smoothness and back to normal.

There is still just barely...BARELY a vibration right off idle, nothing that's noticable and not NEAR as bad as it was, probably what would normaly be absorbed by the OEM slush mounts.

I'm a happy camper now! Taking it on a road trip from Houston to Hot Springs this weekend.

67electro
08-03-11, 04:22 PM
Lesson learned... I will always have a flywheel balanced with the pressure plate attached when ever doing a clutch job.

I will have to find someone here in PHX to balance my ls7 kit before I put it in.

DougNuts
08-03-11, 05:05 PM
Sounds like I need to find someone local to do this for me. If I had another car, I'd do it myself, but I don't think I want to try and fit this in over a weekend again, not so soon after I just did the job.

67electro
08-03-11, 05:23 PM
@DougNuts If I lived closer, I would help you.

I go to this place near by called DIYPerformanceAutomotive. they have 6 Lifts and a few other bays without lifts, tools, etc. they charge 20 bucks an hour for a bay w/ lift + tools. thy have a trans jack, screw jacks, etc.

CadzillaTN
08-03-11, 06:53 PM
Good news AG!

I guess it's fair to say that once the trans is removed for any reason, if not mated back perfectly, you could obtain these vibes..and when installing a new setup, get it balanced first. Of course, that would mean more labor since the fw doesn't necessarily have to come out on a clutch install.

Odd that the vibration rpm range is similar for all of us, even with different clutch kits and flywheels.

So, is removing the trans/clutch/fw in your home garage on jackstands feasible? I assume you'd have to jack out up quite far. I have access to a lift but can't leave it there :(..plus I have no clue where to take the parts to get balanced. If someone screws it up, thats a heck of alot of labor to do again..

I might as well remove them all and get them balanced. I might ship off my trans as well to someone like rpm, to see if the input shaft is damaged from all the vibration. This would be a slam dunk in my bid to get it replaced under my (now expired) warranty.

DougNuts
08-03-11, 08:01 PM
Good news AG!

I guess it's fair to say that once the trans is removed for any reason, if not mated back perfectly, you could obtain these vibes..

What do you mean about this? I just manhandled mine back in place. :mad2:



and when installing a new setup, get it balanced first. Of course, that would mean more labor since the fw doesn't necessarily have to come out on a clutch install.

Odd that the vibration rpm range is similar for all of us, even with different clutch kits and flywheels.

I agree that it's very odd and I also feel it shouldn't be necessary.


So, is removing the trans/clutch/fw in your home garage on jackstands feasible? I assume you'd have to jack out up quite far. I have access to a lift but can't leave it there

I might as well remove them all and get them balanced. I might ship off my trans as well to someone like rpm

I drove the car up on ramps, jacked up the rear end and then jacked up the front until the tires were just barely on the ramps. When I get the time (a few months) I suppose I'll pull the transmission again and find someone to balance the assembly for me.

CadzillaTN
08-03-11, 10:49 PM
I meant the whole fw/c/pp unit, not sure why I said trans.

Your case seems to be different because you've had 2 setups and still have the vibes.. If yours ends up being the unit balance, that would be reassuring...I'd hate for this trans to be ruined over a stupid flywheel. Ive always treated it with care: never powershifted it, never under 65-70 in 6th, perfect rev matches, slowly click into gears, multiple fluid changes, etc.

I still want a new transmission. GM put a dm flywheel in a 400hp car. They need to understand that if that POS fails and ruins the transmission while under warranty, you provide new transmission.

If the dealer had reacted when I first mentioned the vibes, I may have never had a problem. It was still subjective due to no "comparison" cars. I convinced a local guy to bring in his V. Only then did they realize the vibes were not normal (this guy even has all the bmr parts on his V)....

AG'S-V
08-04-11, 11:47 AM
Fly, disc and pressure plate were zero balanced seperately and then together and marked before putting in the car.

$60 at a local machine shop my guy uses.

kevm14
08-04-11, 12:41 PM
This is a tip worth publicizing. Sounds like some come less than perfectly balanced, which is disappointing.

AG'S-V
08-04-11, 12:47 PM
Yes...it is.

BUT, this clutch set-up was not meant for our application either.

The C5 Z06 and reg C6 guys run into the same issue from my readings...hanging on the back of a LS7 it might be smooth as a baby's bum however.

67electro
08-04-11, 12:58 PM
Out of balance is out of balance. when they assemble an engine at GM, they mount the Flywheel and balance the engine as an assembly and add weights to the flywheel.
so when replacing a flywheel, it has to be zero balanced, they don't do a good job of that in mass prod.

AG'S-V
08-04-11, 02:41 PM
True

darkman
08-04-11, 05:17 PM
Out of balance is out of balance. when they assemble an engine at GM, they mount the Flywheel and balance the engine as an assembly and add weights to the flywheel.
so when replacing a flywheel, it has to be zero balanced, they don't do a good job of that in mass prod.

http://www.cadillacforums.com/forums/2004-2007-cadillac-cts-v-performance/231540-ls7-flywheel-should-i-get-balanced.html#post2611217

DougNuts
08-04-11, 07:00 PM
Keep in mind guys, I had this problem before installing the LS7 flywheel/clutch/PP. Exact same vibration, exact same RPM.

CadzillaTN
08-04-11, 09:48 PM
The story of Fatty Flywheel

Fatty Flywheel was shot, so the dealer decided to replace her. Rocco Retardo was the tech that got the assignment...Uh Oh! He doesn't know the first thing about working on a V..he's got no manuals either. He's only getting paid for 1.3 shop hours, and it's friday, so he's ready to go. Fatty is in good, certified Goodwrench hands! Well, Rocco breaks your shifter trim, incorrectly re-installs your shifter base/plate and probably everything else northward. It shifts much rougher than when you took it in. Sometimes, if you're lucky, when you move the stick to right, it'll just get hung up on something... won't come out of gear or whatever the f it's getting jammed on, you just have to force it around until it lets go... chances are something else under there is just not right.

The End

67electro
08-17-11, 03:12 PM
lol, Dougnuts, and Cadzilla, how are things going with this?

I have my Ls7 kit, I need to order the bleeder still.

I can only find one place here in phoenix that will balance the assembly, and that's Chuck Speed and Rv center. they want 80 bucks.

AG'S-V
08-17-11, 04:10 PM
I'm now chasing a vibration in 5th gear that kicks in about 50 mph and is there part-throttle up to about 80.

I think at some point the drive shaft wasn't indexed right...carrier bearing looks/feels fine.

>.<

67electro
08-17-11, 04:25 PM
if its only in 5th gear, I doubt its the drive shaft... the drive shaft wouldn't care what gear you are in..

what could care, would be the output shaft of the transmission, or the counter shaft for 5/6

if there is an issue with the shaft bearings, then it would cause an issue depending on what gear you are in, because the different gears put load on the shaft in a different place.

a few inches apart does make a different if its a rotational vibration... think of it as being out of balance, if the shaft is allowed to wobble in its bearing races.

its my opinion that is is more likely transmission related.

Here is a picture of the fixed 5-6 Gear being removed directly from the tail/main shaft.
78994

Here is a picture of the counter shaft that selects between the 5th and 6th gears using the shift forks, etc.
78995

these pictures are from this post about rebuilding:
http://www.ls2.com/forums/showthread.php?t=1877

AG'S-V
08-17-11, 06:20 PM
Yeah, that's what I'm afraid of...what's a tranny rebuild running these days for a T56?

CadzillaTN
08-17-11, 08:25 PM
lol, Dougnuts, and Cadzilla, how are things going with this?

I have my Ls7 kit, I need to order the bleeder still.

I can only find one place here in phoenix that will balance the assembly, and that's Chuck Speed and Rv center. they want 80 bucks.

No progress, I parked the car. Looks great sitting still. Some days I just sit in it and pretend it's 2008 and I'm driving with no vibrations......ahhh yes....smooth...

DougNuts
08-18-11, 10:45 AM
No change on my end, yet. After poking around on this site the other day, I decided to buy a new transmission mount from Creative Steel to see if that does anything. It arrived yesterday (quick!) and I may try to put it on tonight if I have a chance.

CadzillaTN
08-18-11, 02:26 PM
Looking forward to that feedback as I plan to do the same. I'm not expecting it to be resolved but hopefully it will be lessened simply because there'll be less strain on the drivetrain..

DougNuts
08-18-11, 11:33 PM
I have good news to report! The Creative Steel transmission mount made the car much, much better. The vibration isn't completely gone, but I'd give it a 90% reduction in harshness! Almost as good is how much the shifting has improved with the new trans mount. I need to get some more time behind the wheel to be sure, but so far I'm happy with the car again.

WesH8398
08-20-11, 10:55 AM
I have good news to report! The Creative Steel transmission mount made the car much, much better. The vibration isn't completely gone, but I'd give it a 90% reduction in harshness! Almost as good is how much the shifting has improved with the new trans mount. I need to get some more time behind the wheel to be sure, but so far I'm happy with the car again.

That's music to my ears. The first mod I did with my V was new motor mounts in an effort to get rid of engine vibes around the same rpm as you describe (but in all/any gear). Unfortunately the new mm's didn't do much for the vibes and I've just lived with it for the past year. At the time I got the mm's I also got the trans mount, but most people said it wouldn't help anything so its just been sitting on a shelf collecting dust. This is definitely motivation to install that thing!!

DougNuts
08-21-11, 05:19 PM
That's music to my ears. The first mod I did with my V was new motor mounts in an effort to get rid of engine vibes around the same rpm as you describe (but in all/any gear). Unfortunately the new mm's didn't do much for the vibes and I've just lived with it for the past year. At the time I got the mm's I also got the trans mount, but most people said it wouldn't help anything so its just been sitting on a shelf collecting dust. This is definitely motivation to install that thing!!

Yes, throw it in there, it only took about 45 minutes to install. After driving the car for a few days, I can say that the vibration is not fixed, but it is reduced with the new transmission mount.

WesH8398
08-21-11, 07:06 PM
Since it sounds like you installed it yourself, can you tell me if it was necessary to remove the exhaust in order to get the mount out/in? Or were you able to do it with the pipes in place?

DougNuts
08-21-11, 11:26 PM
Since it sounds like you installed it yourself, can you tell me if it was necessary to remove the exhaust in order to get the mount out/in? Or were you able to do it with the pipes in place?

You need to drop the front of the exhaust (4 bolts), but that's it. Caution: They may be rusted.

67electro
08-22-11, 11:21 AM
yeah, mine were rusted.. and one broke. they were easy to remove with a good wrench and socket, but like I said, one broke. took a trip to ace hardware and got a stainless bolt to replace the broken stud, just threaded it in through the back. and it worked fine.

WesH8398
08-22-11, 03:54 PM
yeah, mine were rusted.. and one broke. they were easy to remove with a good wrench and socket, but like I said, one broke. took a trip to ace hardware and got a stainless bolt to replace the broken stud, just threaded it in through the back. and it worked fine.

Lucky it broke where you still had a decent amount of threads left to use!

I think I'll be soaking the crap out of those suckers with penetrating oil before I go at em. Soak, heat (drive), allow to cool, soak, repeat. lol I wonder if using an impact on them would be better or worse in terms of breaking bolts...

67electro
08-22-11, 04:11 PM
I would not use an impact... if you are worried about breaking it, use a regular 3/8 drive ratchet, that way its harder to break it. and do use the penetrating oil.

many people see a rusty bolt and they go at it with an impact, or 1/2 drive, or breaker bar.. and that's great and all... but not if you snap the bolt.

67electro
08-22-11, 04:12 PM
no swatting flies with atom bombs :)

WesH8398
08-23-11, 12:50 AM
no swatting flies with atom bombs :)

lol I like that saying. As for the impact, I thought that maybe it would rattle the bolt loose easier than trying to break it lose via ratchet or breaker bar. I was thinking of turning the torque right down and just rattling the crap out of it til it came loose, not just going at it with 300 foot pounds and hoping for the best. lol