C5 Clutch noise

[Mannings]

Need some diagnostics help.

I just started getting what sounds like a rubbing / seized bearing noise about a week ago. Weekend driver for the last 4 years.

1999, MN6, 160K (I've had it since new). 40K ago I had a complete clutch, slave, master cylinder, TO bearing all C6Z components, Output Shaft and Torque Tube bushings changed.

Problem: I start car in neutral pedal down no noise, start letting off the pedal to go up (engage) and noise starts at about 2" of off the floor. Noise continues with pedal up and in neutral. The noise varies in volume. Sometimes it gets better after I drive for a while.

[Rich Z]

Does the noise persist if the engine is running, clutch pedal all the way up, with transmission in gear while you are driving?

[Mannings]

Yes Sir, so I don't believe it's not the TO bearing

[gmjunkie]

Where does the noise sound like it's coming from,Front,Middle or Rear of drive line?

Did they change out the 3 bearings in the toque tube along with the bushings?

[Mannings]

Originally Posted by gmjunkie

Where does the noise sound like it's coming from,Front,Middle or Rear of drive line?

Did they change out the 3 bearings in the toque tube along with the bushings?

Thanks for the reply Junk. Sound is coming from clutch area. I'm not sure about the bearings but I did see the old bushings.

[gmjunkie]

Originally Posted by Mannings

Thanks for the reply Junk. Sound is coming from clutch area. I'm not sure about the bearings but I did see the old bushings.

I've ruled out Pilot and T O bearings,Any noise from them would stop after clutch was engaged. That leaves the 3 bearings in the toque tube and the transmission in put shaft bearing,Can you feel the noise in the shifter???

[Mannings]

Junk: Shifter has no vibration?

[Rich Z]

You know, I still get an intermittent screech from my drivetrain when I slowly engage the clutch from a standstill. Only happens every now and again, and I can definitely feel a vibration in my gear shift shaft when it happens. Only happens when the clutch starts to engage, and then ceases when fully engaged. Seems to be when I SLOWLY engage the clutch and not so much if I am quick about letting up on the clutch pedal.

So maybe something similar?

Would feeling vibration in the gearshift shaft indicate the bearing on the transmission input shaft?

I wonder if my transmission input shaft bearing got damaged from all the crap that happened from the Pfadt driveshaft fiasco?

[gmjunkie]

Originally Posted by Rich Z

You know, I still get an intermittent screech from my drive train when I slowly engage the clutch from a standstill. Only happens every now and again, and I can definitely feel a vibration in my gear shift shaft when it happens. Only happens when the clutch starts to engage, and then ceases when fully engaged. Seems to be when I SLOWLY engage the clutch and not so much if I am quick about letting up on the clutch pedal.

So maybe something similar?

Would feeling vibration in the gearshift shaft indicate the bearing on the transmission input shaft?

I wonder if my transmission input shaft bearing got damaged from all the crap that happened from the Pfadt driveshaft fiasco?

Not necessarily Rich,But it's possible to tell whitch bearings are possibly bad or making noise by the noise or vibrations created in different gear and rpm scenarios through the drive line. If I was able to drive Mannings car,I'd bet within a few miles I could tell you where to look to fix it.

Now just a quick question on your car,How many miles are actually on your clutch?

I had to go through my trans at 92,000 miles and so while I was at it I replaced my clutch (LS1 1800# clamping force)with a Genuine GM LS7 (2800# clamping force)Matched Clutch/ Disk,Pressure Plate and Flywheel. It had kind of a Grabby,Chatter Screech at first that you could feel in the shifter that was really bad at first,after about 35-50 miles got more and more intermittent,after 7,000-8,000 miles it hasn't done it since!19,000 on it now!

The warranty papers with the clutch noted that it was completely normal for it have some shutter and noise until the disk seated into the flywheel and pressure plate,(6,000-10,000 miles)

[Rich Z]

Not sure of exactly how many miles on the clutch right now, but it was put in the car back at the beginning of August 2012. So likely I've got a couple thousand miles on it in the 16+ months it's been in there. I babied it for the first 500 or so miles for break-in, and have never really abused it at all the entire time. If anything, I still treat the car like it's made out of egg shells.

I have read accounts of people complaining about the Centerforce clutches sometimes being noisy, so it just may be I got one that isn't as quiet as I would like. Just not even tempted to pull out the drivetrain just to replace the clutch to see, I guess. So if that intermittent screech is a warning of some sort of impending failure, I'll just wait until what ever it is breaks, THEN fix it. If the noise is just an irritant, then I can live with it till I NEED to pull out the drivetrain, and then try to figure it out.

If I thought I could reproduce the noise on demand, I would take it to Shane at the local Chevy dealership just so I could get his opinion about what is going on. But it's just not that predictable.

Heck, I've probably got some video around here somewhere that I took while driving the car where the noise makes itself evident. I thought about getting one of those GoPro camcorders and trying to mount it at strategic spots to try to pinpoint where the noise is coming from, but I'm not sure that even that would work.

The practical side of me wants me to just not worry about it, but the perfectionist side sometimes gnaws on my leg to try to figure it out. I'm trying to keep that perfectionist side in check lately. It can be a pain in the ass sometimes.