: anyone heard this clutch sound?



leosul@verizon.net
07-14-11, 10:51 PM
2006 V with 6K miles, never abused (well a few burnouts to test for wheel hop). Nice and quiet at work parking lot tonight with windows down. I noticed backing up slowly or going forward in first, when I push in the clutch I hear a very light sort of double "thunk-thunk" coming right from where I believe the clutch lives. In the old days we would have said "throwout bearing is going," but I doubt with this history and low mileage that is the case. Is there anything adjustable at all in the clutch assembly? This is definetly my weak point-haven't driven anything with a clutch except motorcycles in a long time. Any thoughts or ideas appreciated.

06BlackV
07-15-11, 05:33 AM
this clunk that u hear is normal, to lessen the "clunk" ur timing of the rpm and clutch engagement has to be almost perfect,,,, i upgraded my clutch to the ls7 setup , it greatly reduced it but not 100 percent

OneFast V
07-15-11, 11:27 AM
Its a combination of the dual mass flywheel along with the unloading of the rear differential on a soft bushing.

Castro
07-15-11, 03:11 PM
Oh man your mileage is so low you haven't had parade clunk yet! I bet your diff is silent too. You'll soon join our club for real.

leosul@verizon.net
07-16-11, 10:39 AM
What exactly is parade clunk? The clunk sound when you push in the clutch before shifting?, or something else...

darkman
07-16-11, 03:08 PM
What exactly is parade clunk? The clunk sound when you push in the clutch before shifting?, or something else...

The definition of parade clunk, which is a term apparently coined by Corvette owners, depends somewhat on who you ask, so I can only provide my opinion.

On my 05 V, I only encounter parade clunk twice on the typical drive. When I back out of my driveway the first clutch release is accompanied by a clunk as the slack in the drivetrain is taken up. Once out of the driveway, I experience the parade clunk one more time as the drivetrain reverses the slack to accommodate forward movement. I will not experience the clunk again unless I unload the drivetrain by using reverse again.
The basic source of this driveline slack in the CTS-V is the limited slip differential. This can be verified by lifting the rear wheels off the ground, and twisting the driveshaft. It takes something like a quarter turn of the drive shaft before the rear wheels will turn. Since the rotational back-lash associated with the ring and pinion gear is only a few thousandths of an inch measured of rotation, the "driveshaft-to-wheel lag" cannot be explained by gear back-lash and must therefore, be attributed to the operation of the limited slip clutch packs.

Given this basic source of “parade clunk” there can be several other factors that amplify this driveline slack which become more noticeable with age/mileage. These aggravating factors include the differential bushing which contributes its own slack when worn; the dual-mass flywheel, which is spring loaded; the motor mounts which are liquid filled and can leak; other components in the driveline subject to rotation.

Houdini
07-16-11, 05:16 PM
Mine has been clunking like crazy the last few days... This time it sounds like both the flywheel and the rear diff bushing again...sigh. I just have to pay attention and drive around it haha.

lollygagger8
07-18-11, 10:49 AM
Most of it comes from the driveshaft IMO. When I replaced my first DS, it was super silent again (beside diff whine) As soon as I gave it a few love taps with the skinny pedal, noisy all over again. The carrier bearing is such a weak link!! <- 2nd only to the diff.