Strange noises after clutch install.
Thread Starter
Burning Brakes
Joined: Apr 1999
Posts: 1,161
Likes: 0
From: Texas
Strange noises after clutch install.
I put a new OEM clutch in at 69K miles on my '96 LT4. I did what I thought was a VERY meticulous job. I had the original flywheel resurfaced rather than buying a new one. I felt I could get away with a resurface job since 69K is relatively soon for a clutch job on a mildly driven vette.
All was well for about 3500 miles then it started making a short chirp sort of noise when I shifted into 3rd and/or fourth. Kind of like a tire chirp noise but not as high pitched. Now lately it has started making a noise like I got a box of rocks rolling around inside the bell housing, kind of muffled though.
Anyone got any ideas what might be going on? I'm REALLY not looking forward to tearing it back apart so soon.
Thanks
dr
All was well for about 3500 miles then it started making a short chirp sort of noise when I shifted into 3rd and/or fourth. Kind of like a tire chirp noise but not as high pitched. Now lately it has started making a noise like I got a box of rocks rolling around inside the bell housing, kind of muffled though.
Anyone got any ideas what might be going on? I'm REALLY not looking forward to tearing it back apart so soon.
Thanks
dr
Thread Starter
Burning Brakes
Joined: Apr 1999
Posts: 1,161
Likes: 0
From: Texas
Re: Strange noises after clutch install. (h rocks)
I meant to mention above that the "box of rocks" noise is only sometimes happening when I am driving slow like up the driveway. The car still shifts and drives just fine, its just making noise sometimes.
I have read here in the past where folks have resurfaced rather than replaced. Is the practice usually unsuccessful?
What happens if I just drive it like it is for 10K more miles? I don't have time to gut it again right now.
thanks
dr
I have read here in the past where folks have resurfaced rather than replaced. Is the practice usually unsuccessful?
What happens if I just drive it like it is for 10K more miles? I don't have time to gut it again right now.
thanks
dr
Thread Starter
Burning Brakes
Joined: Apr 1999
Posts: 1,161
Likes: 0
From: Texas
Re: Strange noises after clutch install. (fullboogie)
Yes, new T/O bearing, new pressure plate, new pilot bushing. Complete OEM Valejo clutch kit from Carolina Clutch.
I do recall the shop took off quite a bit of material, it seemed to me, when they surfaced the flywheel. I'd guess more than 60 thousandths. The flywheel surface seemed to be cone shaped. When the cutting wheel began its work it was taking off material only around the outside edge at first, the grounded area slowly moved inward from the outside as it went around the flywheel.
Could that be the prob?
I do recall the shop took off quite a bit of material, it seemed to me, when they surfaced the flywheel. I'd guess more than 60 thousandths. The flywheel surface seemed to be cone shaped. When the cutting wheel began its work it was taking off material only around the outside edge at first, the grounded area slowly moved inward from the outside as it went around the flywheel.
Could that be the prob?
Safety Car
Joined: Apr 1999
Posts: 4,623
Likes: 2
From: Ohio
Re: Strange noises after clutch install. (DavidR)
With the additional info, it could also be that the balance of the FW was altered and it could be slightly out. Don't forget, the motor is externally balanced, and the FW's are counterbalanced to offset any imbalance on the back end of the motor. You may just be hearing some ZF noise which is very common. If you have not changed your trans fluid in 20,000 miles or more, do it, then run it for about 200 miles, then do it again. ONLY with factory fill. (Pul-eeezzzeee, no Red Line debate on this thread again!) You WILL be surprised at how much the first change quiets things down, then how smooth the second change makes it and keeps it.
Drifting
Joined: Dec 1999
Posts: 1,319
Likes: 2
From: Douglasville GA
Re: Strange noises after clutch install. (DavidR)
Sorry to tell you this, but h rocks is correct, these flywheels are not to be cut. What happens is the fluid leaks out and then the dual mass dampening is gone, and the two halves are free to rotate.
The sound you describe is basically the same as a single mass flywheel. Either your dualmass has lost all fluid, or siezed into a single mass.
Dual mass replacement flywheels are not cheap!
Tom Melton
82 CE
86 Z51 Coupe with 1996 ZF6
The sound you describe is basically the same as a single mass flywheel. Either your dualmass has lost all fluid, or siezed into a single mass.
Dual mass replacement flywheels are not cheap!
Tom Melton
82 CE
86 Z51 Coupe with 1996 ZF6
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Burning Brakes
Joined: Oct 2002
Posts: 1,152
Likes: 1
From: Wichita KS
Re: Strange noises after clutch install. (h rocks)
(Pul-eeezzzeee, no Red Line debate on this thread again!)
I'll agree, the dual mass isn't designed to be resurfaced, you could probably get away with a few thousandths’ (.010-.015) of surfacing but a 1/16" is a little too much to remove.
They do go bad often at higher miles, especially if ran hard or if the motor is now making extra power after some mods..
Sounds are kinds hard to interpt over the internet but the sound you describe is that of a bad dual mass..Call Carolina Clutch back up & describe the sound to em' see what they say..Ford Powerstroke trucks share a similar dual mass flywheel & ZF Trans, they also have the problem of DM's going bad, often after hauling a stout/heavy load..
Good luck.. :seeya
Melting Slicks
Joined: Oct 2000
Posts: 3,010
Likes: 1
From: Sweden/Stockholm
Re: Strange noises after clutch install. (superlund)
is the engine external balanced?!, that should mean that you never could swap FW. You have to take the engine out and reblance the hole thing with the new flywheel inplace. I Dont think that.. :confused:
[Modified by devilfish, 1:44 PM 12/31/2002]
[Modified by devilfish, 1:44 PM 12/31/2002]
Drifting
Joined: Dec 1999
Posts: 1,319
Likes: 2
From: Douglasville GA
Re: Strange noises after clutch install. (devilfish)
Yes, externally balanced, the L98, LT1 and LT4 are all externally balanced. The flywheel for each has additional weight on one side of the flywheel to make balance. Actually I think ALL one-piece seal GM cranks are externally balanced.
Of course you can make a one-piece seal crank internally balanced, but it is not from GM that way.
Now how do you replace the flywheel - balance the new one to the old one, or do as GM does, and just use another from the parts bin.
Tom Melton
82 CE
86 Z51 Coupe
Of course you can make a one-piece seal crank internally balanced, but it is not from GM that way.
Now how do you replace the flywheel - balance the new one to the old one, or do as GM does, and just use another from the parts bin.
Tom Melton
82 CE
86 Z51 Coupe
Burning Brakes
Joined: Apr 2001
Posts: 994
Likes: 0
From: Jamison PA
Re: Strange noises after clutch install. (Utahvette)
When I did my clutch replace this past summer I only roughed the flywheel surface with a ScotchBrite pad. The flywheel wasn't in bad shape, only had 40k on it. There is a freeplay measurement on the flywheel to see if the dampening is within specs. If it's not within spec GM says to replace. You might be hearing that noise as well.
Melting Slicks
Joined: Oct 2000
Posts: 3,010
Likes: 1
From: Sweden/Stockholm
Re: Strange noises after clutch install. (tommelton)
"use another from the parts bin", what to you mean about that?
so you mean that if get a brand new FF from GM, I must balance it like my old FF? Or can you just put it in?
[Modified by devilfish, 3:23 PM 1/1/2003]
so you mean that if get a brand new FF from GM, I must balance it like my old FF? Or can you just put it in?
[Modified by devilfish, 3:23 PM 1/1/2003]
Team Owner
Joined: May 2001
Posts: 25,058
Likes: 1,265
From: Virginia
St. Jude Donor '11
Re: Strange noises after clutch install. (devilfish)
I just took your suggestion and checked out the Swedish corvetteforum and I couldn't understand a single word..do they have a translation expert on hand?... :lol: :lol: :lol: does no good if you can't understand a word they are saying... :p:
[Modified by Yello95, 1:18 AM 1/2/2003]
[Modified by Yello95, 1:18 AM 1/2/2003]
Melting Slicks
Joined: Oct 2000
Posts: 3,010
Likes: 1
From: Sweden/Stockholm
Re: Strange noises after clutch install. (Yello95)
heheh :lol:
Well I can translate it for ya. But I can asure you that there is nothing printed there that you cant get helpt with here, this is THE corvetteforum ;)
Well I can translate it for ya. But I can asure you that there is nothing printed there that you cant get helpt with here, this is THE corvetteforum ;)
