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I purchased a 2013 C6 base model back in March from the local dealership. It had 29k miles. It is a manual trans.
When I first drove the car I noticed the clutch chattered if slipped at low RPM. I assumed the clutch was glazed and I had the dealership replace it. It still chattered. They said the flywheel must be bad. I had them replace the flywheel and the clutch again under warranty. It still chatters.
The dealership doesn't know and I am at a loss for an explanation. When looking at the clutch parts, both the original and the replacements, there is no sign of glazing or wear. It looks perfect.
If you are sitting still, rev to about 1200 RPM slightly release the clutch the car will just sit there and shake.
Please help! I am pulling my hair out because the dealership just doesn't seem to care and they can't figure it out. This has been going on for 8 months.
Any ideas?
Last edited by qwazipsycho; 11-24-2017 at 07:59 PM.
I purchased a 2013 C6 base model back in March from the local dealership. It had 29k miles. It is a manual trans.
When I first drove the car I noticed the clutch chattered if slipped at low RPM. I assumed the clutch was glazed and I had the dealership replace it. It still chattered. They said the flywheel must be bad. I had them replace the flywheel and the clutch again under warranty. It still chatters.
The dealership doesn't know and I am at a loss for an explanation. When looking at the clutch parts, both the original and the replacements, there is no sign of glazing for wear. It looks perfect.
If you are sitting still, rev to about 1200 RPM slightly release the clutch the car will just sit there and shake.
Please help! I am pulling my hair out because the dealership just doesn't seem to care and they can't figure it out. This has been going on for 8 months.
Standard clutch for all the C6's short of the zr1 is, the clutch for the LS-7. The LS-2 did have a lighter clutch, but it replacement is still the LS-7 clutch.
As for the clutch slipping, it semi normal at high RPMS, since the centrifal force of the heaver clutch will slow down the clutch fully locking up quickly isntead. but this is high rpms, and not something that should be happening at 1.2k RPM's isntead.
If they did a full replacement of the clutch, including the slave cylinder as well, then really don't see how this is happening, short of a problem in the torque tube instead.
Hence when they did the clutch, should have been new fly wheel, new flywheel pilot bearing, new pressure plate and disc, and new slave cylinder with it new throw out bearing as well (full monty is change out).
Now lets move to the torque tube, and although not a lot of parts in it, if the bearings are worn on the slave side, then even with a new flywheel bearing, it can cause problems with disco not moving correctly forward when the pressure plate applied pressure, and could be causing the problem isntead. Also, could be that the shaft splines are worn/bur city, and why the disc is not moving back forward to engage the flywheel surface when the pressure plate side re-engages the disc.
To be blunt, if the car is still under warranty, get a hold of Gm corporate to go over the problem, and chances are they may have you take the car to another dealer to solve the problem isntead.
If not under warranty, then again, you will need to find another shop (that is trustworthy), but make sure that the shop documents what they find as the problem, and what is required to fix the problem. You will need this documentation in small claims court when you go to sue the first dealer to get those funds back when the car is correctly repaired in the end by the second shop.
FYI, the dealer you did take the car to, do they even have Vette trained tech or GM Master Mechanic on staff, and who did the work to the car in the first place? Hence some dealers that don't sell a lot of vets have neither, while dealers that do sell and service lots of vets have both, and in most cases on these dealers that do sell and service vets, a different area that they will work on the vets only instead.
Standard clutch for all the C6's short of the zr1 is, the clutch for the LS-7. The LS-2 did have a lighter clutch, but it replacement is still the LS-7 clutch.
As for the clutch slipping, it semi normal at high RPMS, since the centrifal force of the heaver clutch will slow down the clutch fully locking up quickly isntead. but this is high rpms, and not something that should be happening at 1.2k RPM's isntead.
If they did a full replacement of the clutch, including the slave cylinder as well, then really don't see how this is happening, short of a problem in the torque tube instead.
Hence when they did the clutch, should have been new fly wheel, new flywheel pilot bearing, new pressure plate and disc, and new slave cylinder with it new throw out bearing as well (full monty is change out).
Now lets move to the torque tube, and although not a lot of parts in it, if the bearings are worn on the slave side, then even with a new flywheel bearing, it can cause problems with disco not moving correctly forward when the pressure plate applied pressure, and could be causing the problem isntead. Also, could be that the shaft splines are worn/bur city, and why the disc is not moving back forward to engage the flywheel surface when the pressure plate side re-engages the disc.
To be blunt, if the car is still under warranty, get a hold of Gm corporate to go over the problem, and chances are they may have you take the car to another dealer to solve the problem isntead.
If not under warranty, then again, you will need to find another shop (that is trustworthy), but make sure that the shop documents what they find as the problem, and what is required to fix the problem. You will need this documentation in small claims court when you go to sue the first dealer to get those funds back when the car is correctly repaired in the end by the second shop.
FYI, the dealer you did take the car to, do they even have Vette trained tech or GM Master Mechanic on staff, and who did the work to the car in the first place? Hence some dealers that don't sell a lot of vets have neither, while dealers that do sell and service lots of vets have both, and in most cases on these dealers that do sell and service vets, a different area that they will work on the vets only instead.
When I first bought the car, the clutch chattered. 1st attempt, they replaced the pilot bearing, turned the flywheel, replaced disc, pressure plate, throwout bearing, and slave cylinder. Still chatters but not as bad. They also replaced the entire torque tube assembly under warranty.
2nd attempt they replaced the flywheel, all clutch parts again under warranty, and the master cylinder. Still chatters - worse than originally.
Another tech looked at it and said the harmonic balancer is faulty but that's not what's causing the chatter. The car is currently at the dealer and they are consulting with GM tech support.
Keep in mind that I'm on an island in the Pacific and there is only 1 GM dealership here. The quality of service here is "3rd world country".
Last edited by qwazipsycho; 11-22-2017 at 01:17 PM.
The level of incompetence and laziness you experience when living in Hawaii is unbelievable.
The dealership just called and said that they, and GM corporate (which I don't believe) have declared the condition in my vehicle NORMAL.
Yeah, it's normal to have the car buck like a bull when taking off from a slow start or up a hill. If you're clutch is trash, sure, then it's normal. Or is it just that it's a GM vehicle?
I've never had any love or respect for GM even after being a factory trained tech back in the 80's. This just proves to me that they are still the worst car manufacturer on the planet.
Anybody else care to try and explain why a brand new clutch chatters like it's glazed or warped?
Worst case, then can either ship the car to the main land to have it fixed correctly fly someone from the mainland to come fix it at the dealer, or just by the car back under the lemon law.
Hence its a vet, so you really don't need to give it gas to clutch out from a dead stop, and if you do clutch out with say 2K rpms quickly, should lock up the clutch solid without chatter (but going to end up with a ton of wheel hop as the tires loose grip instead).
IIRQ, there are couple of lads on the islands that own vets, so have one of the drive the car to tell you if the clutch is normal or not. Hence what you think may be the clutch slipping, is just wheel hop as the clutch locks up instead.
Worst case, then can either ship the car to the main land to have it fixed correctly fly someone from the mainland to come fix it at the dealer, or just by the car back under the lemon law.
Hence its a vet, so you really don't need to give it gas to clutch out from a dead stop, and if you do clutch out with say 2K rpms quickly, should lock up the clutch solid without chatter (but going to end up with a ton of wheel hop as the tires loose grip instead).
IIRQ, there are couple of lads on the islands that own vets, so have one of the drive the car to tell you if the clutch is normal or not. Hence what you think may be the clutch slipping, is just wheel hop as the clutch locks up instead.
Hey Dano, thanks for the reply. I will be following up with GM corporate next week. I hope you're right. From what the dealership is telling me, they believe these incompetent techs. This dealership simply wants to wash their hands of this car.
I guess I'm not explaining the problem very well. You are correct that these cars don't need any throttle to set off. That's where the problem lies. Not at 2k RPM and dump the clutch. Imagine you're sitting in a traffic jam that's creeping along. You have to hold your foot on the clutch and just release slightly to get moving. That's where the problem is. When setting off, if you give it no throttle it's fine. So flat surfaces and setting off directly do not cause it. Creeping along in traffic or having to set off on an uphill is going to cause the car to shake. If you are fully aware of the condition and you are used to driving the car, you can almost avoid it but that means slipping the clutch excessively at a higher RPM than necessary. It's not a constant problem but it's not right either.
So your comments about wheel hop or misplaced. This is not a "launching" situation but an everyday driving situation.
Not sure how much time you have on the Vet to get used to the accelerator and clutch yet, but is the chugging coming from the rmp's dropping down below 600rms with the use of the gas pedal to let the clutch out?
The throttle has a hesitation responce built into it to increase gas mileage, and once the motor does start to rev, you can surge the idle way past the RPMs you are trying to hold the motor to instead. So it time time leaning the throttle responce delay time, so you can control the motor RPM's correctly.
So lets say that you are on a hill, have enough time on the car to lightly touch the throttle to have the rmps climb to around 1K as you are letting the clutch out to slightly slip the clutch until if fully engages as your holding the 1k rmps (without spinning the rear tires). Are you getting actual clutch chatter from the clutch then, or is back to the problem of the RPMs dropping below say 600rmp to buck the motor isntead.
Really, check around with the local lads that have vets, and have them take the car for a couple of gear shifts to see if they feel any problems with the clutch. The C6 takes some time getting used to it, and without driving the car myself, don't know if the problem is actually the vet, or you just not used to driving it yet isntead.
So to wrap it up, could be clutch problems still with the tech working on it incompetent, or could be that you don't have enough time behind the wheel on the vet to not low rpm buck the motor on inclines isntead.
Hell if you can post a video with the problem (keep the camera aimed at the dash gauges so we can see the RPMS as your working the clutch and gas pedal), and should be able to tell just what the problem is from the sound alone.
Hence the pressure plate is spring loaded to help absorb shock during torque engagement and reverse down shifts torque as well, and if you are bucking the motor as your letting out the clutch, the pressure plate will bounces off both sides of springs from torque and release back and forth; which sounds like hell.
OK, you wanted video here it is. I'd really like some replies from other C6 manual trans owners. Do you consider this normal?
If this is normal it's the worst clutch design EVER. Leave it to GM to take something so perfect and simple and screw it up. This type of harsh vibration is unacceptable in any car.
I agree that it is not normal. Did they replace your throw out bearing or check the plastic bearing support? A bearing that was bent/damaged or a plastic bearing support that had a side that wasn't even with the other could cause this. It causes uneven loading on the pressure plate fingers at that perfect slip point which translates to a shake. Not on my Z, but I have had this problem and that was what it was. The bearing was ever so slightly deformed and it had this exact condition.
The plastic bearing support is the common failure in our cars. They usually melt all the way down and then take out the slave cylinder. It could be on its last leg and is very very easily overlooked as the bearing covers it. The permanent solution is to replace it with either a Monster clutches or Quartermaster billet bearing support.
No guarantees that this is your issue but I would be having a look at it if it were mine.
Last edited by User Omega; 12-02-2017 at 04:44 AM.
I have an 05 with a M6 and it releases completely smooth, so what your experiencing is definitely not normal, this may sound stupid but i'm thinking maybe the friction disc was installed backwards.
I agree that it is not normal. Did they replace your throw out bearing or check the plastic bearing support? A bearing that was bent/damaged or a plastic bearing support that had a side that wasn't even with the other could cause this. It causes uneven loading on the pressure plate fingers at that perfect slip point which translates to a shake. Not on my Z, but I have had this problem and that was what it was. The bearing was ever so slightly deformed and it had this exact condition.
The plastic bearing support is the common failure in our cars. They usually melt all the way down and then take out the slave cylinder. It could be on its last leg and is very very easily overlooked as the bearing covers it. The permanent solution is to replace it with either a Monster clutches or Quartermaster billet bearing support.
No guarantees that this is your issue but I would be having a look at it if it were mine.
This is the first plausible explanation that I haven't been able to explain away. However, I don't know if they replaced the plastic sleeve. Is this normally replaced when the throwout and slave cylinder are replaced? Keep in mind this is all stock GM parts. Is this part separately listed in the parts breakdown diagram above?
I have an 05 with a M6 and it releases completely smooth, so what your experiencing is definitely not normal, this may sound stupid but i'm thinking maybe the friction disc was installed backwards.
Thanks. I didn't think it was normal either but I need you guys to back me up so every reply is a good one.
I don't think it's possible to install the disc backwards. The center section with the springs protrudes on one side and it would hit the flywheel long before the friction material could touch it. You'd never get the pressure plate on. Thanks though. At this point no idea is dismissed without consideration.
This is the first plausible explanation that I haven't been able to explain away. However, I don't know if they replaced the plastic sleeve. Is this normally replaced when the throwout and slave cylinder are replaced? Keep in mind this is all stock GM parts. Is this part separately listed in the parts breakdown diagram above?
The slave, bearing support, and T.O. bearing come as one unit. As far as I know, you cannot buy the parts separately. If you upgrade to a billet bearing support you must first remove the plastic support and install the aftermarket billet unit.
SLAVE CYLINDER - GM (24237634)
It comes complete as you see here. The bearing you see on the end of the slave is resting on that plastic bearing support.
Here is the exploded view. Plastic support on left and billet on the right.
Obviously this is the end result of the melting but its an example of what a few cycles of overheat can do. If your car experienced a mild case of heat to the bearing or support it could be slightly melted leaving the bearing poorly and unevenly supported.
Again, this is just a suspicion. It seems like you have covered all of the other bases. Any of the tq tube bearings or couplers would make noise or cause issues at full pedal release. This is without a doubt a clutch release issue. The hydraulic system will not pulse itself as it is regulated by your foot. Something is unevenly releasing/applying the pressure plate. That leaves one thing. The slave, the throwout bearing, or its support. Good luck and please let us know what you find you resolve the issue.
The slave, bearing support, and T.O. bearing come as one unit. As far as I know, you cannot buy the parts separately. If you upgrade to a billet bearing support you must first remove the plastic support and install the aftermarket billet unit.
SLAVE CYLINDER - GM (24237634)
It comes complete as you see here. The bearing you see on the end of the slave is resting on that plastic bearing support.
Here is the exploded view. Plastic support on left and billet on the right.
Obviously this is the end result of the melting but its an example of what a few cycles of overheat can do. If your car experienced a mild case of heat to the bearing or support it could be slightly melted leaving the bearing poorly and unevenly supported.
Again, this is just a suspicion. It seems like you have covered all of the other bases. Any of the tq tube bearings or couplers would make noise or cause issues at full pedal release. This is without a doubt a clutch release issue. The hydraulic system will not pulse itself as it is regulated by your foot. Something is unevenly releasing/applying the pressure plate. That leaves one thing. The slave, the throwout bearing, or its support. Good luck and please let us know what you find you resolve the issue.
Well I ASSUME all of that was replaced. So I'm back at square 1 but I agree with you 100%. This is a clutch release issue. So if everything has been replaced, the condition remains, I can only assume that maybe the tech didn't actually replace the slave assembly? I am grasping at anything at this point.
Well I ASSUME all of that was replaced. So I'm back at square 1 but I agree with you 100%. This is a clutch release issue. So if everything has been replaced, the condition remains, I can only assume that maybe the tech didn't actually replace the slave assembly? I am grasping at anything at this point.
Just call the dealer and ask. Or look at the bill they gave you. The parts will be listed and the part number I gave you above is correct. I'm betting they never touched it. Under warranty, if it isn't leaking I bet they do not replace it.
The level of incompetence and laziness you experience when living in Hawaii is unbelievable.
The dealership just called and said that they, and GM corporate (which I don't believe) have declared the condition in my vehicle NORMAL.
Yeah, it's normal to have the car buck like a bull when taking off from a slow start or up a hill. If you're clutch is trash, sure, then it's normal. Or is it just that it's a GM vehicle?
I've never had any love or respect for GM even after being a factory trained tech back in the 80's. This just proves to me that they are still the worst car manufacturer on the planet.
Anybody else care to try and explain why a brand new clutch chatters like it's glazed or warped?
Considering all that they replaced, even the torque tube itself under warranty....I would like to believe they are at least trying. Even giving benefit of the doubt and re replacing everything a 2nd time.
That being said in my experience, clutches that i have seen do that are either not oem and bite too hard acting like an on/off switch or the flywheel had hot spots on it. In your case, since bases have been touched it's hard too say. I will add that if they suspect a bad balancer, change that asap. You seem to need it revving quite low to duplicate the shaking and it very well may be the balancer and it's harmonics at that given rpm. it needs to be done anyways so it's not a waste. I have replaced some bad mounts on these cars too, so a bad mount and balancer under load could really cause a shake for sure.
Considering all that they replaced, even the torque tube itself under warranty....I would like to believe they are at least trying. Even giving benefit of the doubt and re replacing everything a 2nd time.
That being said in my experience, clutches that i have seen do that are either not oem and bite too hard acting like an on/off switch or the flywheel had hot spots on it. In your case, since bases have been touched it's hard too say. I will add that if they suspect a bad balancer, change that asap. You seem to need it revving quite low to duplicate the shaking and it very well may be the balancer and it's harmonics at that given rpm. it needs to be done anyways so it's not a waste. I have replaced some bad mounts on these cars too, so a bad mount and balancer under load could really cause a shake for sure.
Well, I'm headed back there now to have the balancer replaced. Did I mention it took them 6 weeks the first time they had the car?? They are telling me it's going to be 2 days to replace the balancer. Yes, they have it in stock. These guys may be GM techs but they function on Maui time. 2 days? Hmm.
Well, I'm headed back there now to have the balancer replaced. Did I mention it took them 6 weeks the first time they had the car?? They are telling me it's going to be 2 days to replace the balancer. Yes, they have it in stock. These guys may be GM techs but they function on Maui time. 2 days? Hmm.
Wow well that's not good timing. Last balancer I did ran me about 1.5 hours
11-17-2017, 02:09 PM
Clutch Chatter
