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?:shrug01:

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

 

[Mannings]

Where does the noise sound like it's coming from,Front,Middle or Rear of drive line?:shrug01:

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]

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]

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.:thumbsup:

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!:thumbsup:

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):thumbsup:

 

[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. :shrug01: I'm trying to keep that perfectionist side in check lately. It can be a pain in the ass sometimes.

 

[Mannings]

Junk: Took the old gal for a 10 mile spin today. I had the noise at start up but 1 mile into the ride all went quiet. I'm thinking it's a Torque Tube bearing going that once heated lubricates it's self. When I parked it I went to neutral and let clutch out, only a faint sound.

Your thoughts.

 

[Rich Z]

Well, my thoughts are that if you are sitting still, and still hearing the noise (even faintly), then it can't be a torque tube bearing. The driveshaft (or propeller shaft, as some call it) isn't rotating at all then. The driveshaft only rotates in the torque tube bearings when the rear wheels are moving. :shrug01:

Of course, there is no natural law in effect stating that you can only have one thing making a noise in the drivetrain.

 

[gmjunkie]

Well, my thoughts are that if you are sitting still, and still hearing the noise (even faintly), then it can't be a torque tube bearing. The driveshaft (or propeller shaft, as some call it) isn't rotating at all then. The driveshaft only rotates in the torque tube bearings when the rear wheels are moving. :shrug01:

Of course, there is no natural law in effect stating that you can only have one thing making a noise in the drivetrain.

Sorry Rich,That ain't the way it works! Any time the clutch peddle is up(Clutch Engaged),the propeller shaft is turning along with Input shaft and bearing,output shaft front bearing,Cluster shaft and bearings,Cluster shaft extension and bearings,5th drive and driven gear and bearings,6th drive and driven gear and bearings,Reverse idler and driven gear and bearings,don't matter if it's in neutral or not! The only time all gears and bearings stop turning in the trans or torque tube,Is when the clutch is down and your not rolling! Of course then the throw out and pilot bearing are turning at whatever RPM the engine is turning,The only bearings in the transmission that are completely stopped during operation are the output shaft front and 4th gear driven gear bearings (4th locks input and output shafts strait through/No gear reduction),1st driven gear bearing when in 1st,2nd driven gear bearing when in 2nd,3rd driven gear when 3rd,5th driven gear bearing when in 5th,6th driven gear bearing when in 6th,Reverse driven gear when in reverse, and the output shaft middle and rear bearings when your not rolling! The reverse gear bearing is the only steel gaged gear bearing in the transmission,if your running 140 mph in 6th, Reverse driven gear is running 140 mph backward on the output shaft,All shaft bearings are steel caged except output rear,It has a nylon cage like 1st,2nd,3rd,4th,5th and 6th driven gears. I've built 5 or 6 of them now besides my own! That's why if I drove Mannings car for a short time through different Gear and RPM scenarios,I could tell him where to look! If you know and understand how it works,You can fix it!:thumbsup:

Hope my rambling helps,I'm a technician not a writer!~!!:thumbsup:

 

[gmjunkie]

Junk: Took the old gal for a 10 mile spin today. I had the noise at start up but 1 mile into the ride all went quiet. I'm thinking it's a Torque Tube bearing going that once heated lubricates it's self. When I parked it I went to neutral and let clutch out, only a faint sound.

Your thoughts.

Have you checked the fluid,and what kind of lubricant is in the transmission,Use only Dextron III , 4 or 5,Dextron 6 will kill the syncro cones over time!:thumbsup:

I just PM'd you my cell # Call Me,I'll be down their after the first of the year it's getting cold here,I want to play my other "World Class Glass"!

 

[Rich Z]

Sorry Rich,That ain't the way it works! Any time the clutch peddle is up(Clutch Engaged),the propeller shaft is turning along with Input shaft and bearing,output shaft front bearing,Cluster shaft and bearings,Cluster shaft extension and bearings,5th drive and driven gear and bearings,6th drive and driven gear and bearings,Reverse idler and driven gear and bearings,don't matter if it's in neutral or not! The only time all gears and bearings stop turning in the trans or torque tube,Is when the clutch is down and your not rolling! Of course then the throw out and pilot bearing are turning at whatever RPM the engine is turning,The only bearings in the transmission that are completely stopped during operation are the output shaft front and 4th gear driven gear bearings (4th locks input and output shafts strait through/No gear reduction),1st driven gear bearing when in 1st,2nd driven gear bearing when in 2nd,3rd driven gear when 3rd,5th driven gear bearing when in 5th,6th driven gear bearing when in 6th,Reverse driven gear when in reverse, and the output shaft middle and rear bearings when your not rolling! The reverse gear bearing is the only steel gaged gear bearing in the transmission,if your running 140 mph in 6th, Reverse driven gear is running 140 mph backward on the output shaft,All shaft bearings are steel caged except output rear,It has a nylon cage like 1st,2nd,3rd,4th,5th and 6th driven gears. I've built 5 or 6 of them now besides my own! That's why if I drove Mannings car for a short time through different Gear and RPM scenarios,I could tell him where to look! If you know and understand how it works,You can fix it!:thumbsup:

Hope my rambling helps,I'm a technician not a writer!~!!:thumbsup:

What did I say that "ain't the way it works"? Here are the original quotes:

Junk: Took the old gal for a 10 mile spin today. I had the noise at start up but 1 mile into the ride all went quiet. I'm thinking it's a Torque Tube bearing going that once heated lubricates it's self. When I parked it I went to neutral and let clutch out, only a faint sound.

Your thoughts.

Well, my thoughts are that if you are sitting still, and still hearing the noise (even faintly), then it can't be a torque tube bearing. The driveshaft (or propeller shaft, as some call it) isn't rotating at all then. The driveshaft only rotates in the torque tube bearings when the rear wheels are moving. :shrug01:

Of course, there is no natural law in effect stating that you can only have one thing making a noise in the drivetrain.

If the car is sitting still, the clutch HAS to be disengaged (meaning clutch pedal is pressed DOWN) or the engine stalls. If the clutch is not engaged (meaning clutch pedal is DOWN), then the clutch disk attached to the input shaft of the propeller (driveshaft) is not moving. Which means the propeller tube is not moving. Which means the transmission gears are not moving. Which means nothing in the differential is moving. The only things still moving are the components of the engine and the pressure plate and flywheel of the clutch assembly. This is when a pilot bearing noise is most likely to make itself known because the crankshaft is moving and the propeller shaft is not. When the clutch pedal is pressed down, this is also the time that the throwout bearing comes under the most stress as it is being forcibly pressed against the fingers of the clutch pressure plate to pull the plate away from the clutch disk and remove the pressure forcing it between the clutch pressure plate and flywheel.

So unless I am SEVERELY mistaken in how the drivetrain works in these cars, I say again, if the car is NOT MOVING, with the clutch being DISENGAGED, then any noise heard will NOT be the torque tube bearings.

Of course, I CAN be severely mistaken, but if that is the case, then I sure would like someone to explain to me how a clutch actually works. Because obviously I don't have a clue....

 

[Rich Z]

Arrgh... Yeah, I am all wet on this. I was thinking the entire time that the transmission was in gear, NOT in neutral. Reading comprehension thingie, I suppose.

So yeah, you are correct. If the transmission is in neutral with the clutch pedal UP, meaning the clutch is engaged, the propeller shaft IS still rotating. The disconnect between engine power and rear wheels takes place within the transmission itself. Duh.....

Sheesh, reading comprehension was ZIP on this one....

 

[gmjunkie]

What did Manning say? When I parked it I went to neutral and let clutch out, only a faint sound.

What did you say? Well, my thoughts are that if you are sitting still, and still hearing the noise (even faintly), then it can't be a torque tube bearing. The driveshaft (or propeller shaft, as some call it) isn't rotating at all then. The driveshaft only rotates in the torque tube bearings when the rear wheels are moving.


Manning said he had it in Neutral with the clutch engaged! (peddle out/up):thumbsup:

So this would apply,All of this is rotating in Neutral with clutch engaged.(peddle out/up) ..........Any time the clutch peddle is up(Clutch Engaged),the propeller shaft is turning along with Input shaft and bearing,output shaft front bearing,Cluster shaft and bearings,Cluster shaft extension and bearings,5th drive and driven gear and bearings,6th drive and driven gear and bearings,Reverse idler and driven gear and bearings,don't matter if it's in neutral or not! That's while setting still,there are more things rotating going through the gears.

So from experience I know that internally lubricated roller bearings get noisier as the lubricant gets warmer and thinner(transmission)and packed sealed bearings(torque tube) can get quieter the warmer the grease gets. So I'd guess that Manning has it right on the torque tube bearings,probly the front one,It catches the most Hell!

But without driving the vehicle,it's really just a guess,as you said there could be more than one thing making the noise!:thumbsup:

Edit
PS I didn't see your above post Rich,I've had 3 calls since I started this post!:banghead:

 

[Rich Z]

Edit
PS I didn't see your above post Rich,I've had 3 calls since I started this post!:banghead:

:lmao:

No worries. I had a bad case of tunnel vision. Guess I'm STILL not used to the concept of a drive shaft BEFORE the transmission instead of behind it. :banghead:

 

[Mannings]

Thanks Rich and Junk.

 

[Rich Z]

Darn shame that it's such a pain in the butt to remove the torque tube.

What's really a killer is when something simple like the pilot bearing goes out, and to replace a $6 item it will cost you around a grand ($$) in labor at a dealership.