corvetteflorida

First some history. This is a 2002 Z06 that has been in two shops for just over two years, then when I brought it home back in November, has been living on the lift in my garage since then while I tried to clean up the mess those two shops left for me. I am NOT a tech, but I have to do what I have to do. I just can't afford to pay a third shop for all that needed to be done.

Anyway, I thought I was out of the woods and home free back at the end of June. Mike Carnaham came down here and tuned my car for me, and except for some very minor issues, the car was driveable. Pretty much EVERYTHING is new in this car. I have never driven a dual disc clutch before, and that coupled with the light aluminum flywheel, I was just having trouble getting the car off of a dead stop without either a lot of chatter, or bogging to a stall. So this past Thursday, I took the car out for a ride, and decided to find a lonely road to just PRACTICE using the clutch from a dead stop to try to get the hang of it. I found such a road and after about a dozen or two starts, the darn open road in front of me started calling my name. So I let it loose up through third gear.

Now, I was at the top of third gear and let off the gas, so I pushed in the clutch and then put the gear shift into neutral. When I let off the clutch pedal, all hell seemed to break loose. Honestly I freaked out, so I don't remember what the heck I did to make the noise stop. Brain freeze had set in. But it did stop. Then I decided to do another dead stop take off, and this time the noise started right at first gear with me just lightly accelerating. It was in gear at the time. I pushed in the clutch and the noise continued until I put the gear shift into second gear and the noise stopped liked flipping a switch.

Playing around was over with. I thought I had a tow truck in my near future. But the odd thing is that I drove the 15 minutes to get back home and didn't have a peep of noise at all. Anyway, here's the video clip that will show you the noise I am talking about.


Anyone got any ideas?

When Mike Carnahan was down here, he did a couple of WOT runs to third gear just like I did, but I was with him and nothing like this happened. Matter of fact, he didn't get any of the chattering like I did, which is why I am assuming my clutch technique just needs some work.

This is a Fidanza 7.6 Ceramic Twin Disc clutch with the aluminum flywheel. There is a Pfadt carbon fiber driveshaft in the torque tube. Transmission and differential are new from RPM. Engine is a new 427 based on a RHS block. Pilot bearing is new, throwout bearing is new.

For the record I have NO faith in the two shops who installed the clutch. The first shop put in an underpowered clutch that got the flywheel scorched. The second shop put in the correct clutch when the first shop owned up to the mistake and brought the replacement.

Yeah, I know the drivetrain needs to come out no matter what it is, but that is beyond my pay grade. I do have a lift, but manhandling the drivetrain is not something I'm prepared to do. I either have to buy a beefy transmission jack, or else take it to the vette tech at the local Chevy dealership. There are no speed shops I am aware of around here (Tallahassee, FL area) to take it to.

So any advice would be greatly appreciated.

corvetteflorida

No ideas from anyone?

Great..... I guess I'm the first person in the universe (or at least from among everyone who has read this thread) to ever have this noise happen on their car...

MYHAWKROCKS

iTrader: (6)

Hard to tell where the noise is coming from without being in the car but it sounds like a bearing noise...possible pilot or throwout. I know you stated theyre new but thats just what it sounds like to me...

corvetteflorida

Today I put the car up on the lift because I wanted to inspect the flywheel to see if there were any sort of witness marks indicating that the starter gear was contacting the teeth of the flywheel when it shouldn't be. But no, I didn't see any indication of that. So while I was there, I decided to check around for everything that might look out of place or be not as I think it should be.

Well yeah, I can see that at least one bolt holding the torque tube bell housing to the engine is not even close to being tightened down, much less torqued to specs....





I can't see any of the other bolts at the top of the bell housing, so no telling if there are others loose up there as well. Honestly, with the number of bolts I have found loose or completely missing, I have to face the possibility that there are bolts loose or missing on the clutch itself, or even on the flywheel possibly being the cause of this racket I've heard.

Lovely..............

corvetteflorida

Just a followup. It looks like two bell housing bolts on the driver side are completely missing. The last shop to work on the car was Aaron Scott at South Georgia Corvette. You would think a guy who had my car to work on for 14 months would have made sure all the bolts were in place and torqued properly before letting me drive it home....

sepsis

iTrader: (7)

Man, can't trust anyone to do a good job on anything anymore.

You gonna pull the trans and check the other bolts?

Exidous

iTrader: (11)

Jacked up.....it's a shame but at least you found it before the trans decided it was staying home when you left for work in the morning....

corvetteflorida

Yeah. I decided to take the car to the local dealership. The vette tech there is about the only one I think I can trust any longer to work on my car. I've been doing all my own wrenching since November when I brought my car back home from South Georgia Corvette but I wanted an expert to inspect the drivetrain. There could be something glaringly obviously wrong, and I might not notice it. I am DEFINITELY not a vette tech...

Anyway, I was driving the car to the dealership on Monday when the clutch failed completely. Limp clutch pedal and it wouldn't go into gear while the engine was running. I was able to put it into first gear when I shut off the engine, and was able to get the starter to move the car fast enough that the engine caught and was able to limp to the dealership that way. It was only a few miles, but still was a "white knuckle" trip, for sure.

Apparently the clutch slave cylinder failed. With any luck that is the only thing wrong and was maybe responsible for the darn unsettling noises I had been hearing. But the tech is going to inspect and replace the pilot bearing anyway, and also check for any loose or missing bolts. I'm hoping nothing else got screwed up by those bolts being missing and the bell housing moving. He's already found a couple of lines too close to the exhaust that must not have been visible to me when I was trying to straighten things out under there. I took a look at the bell housing itself (at least the part I could see) and I'm not sure whether I was looking at cracks or just casting marks. So I guess I just have to wait and see....

sepsis

iTrader: (7)

Let us know what the problem is/was.

Fbodyjunkie06

iTrader: (10)

That sounded like a throwout/pilot bearing that could of possibly been damaged from the bell housing bolts not being torqued properly and/or slave cylinder related.

corvetteflorida

Sorry, been a LOT going on since I originally posted this.

So now for the REST of the story.

The vette tech at the chevy dealership pulled out my drivetrain and I stopped over there to take pics.







And then we have the splines in one of the clutch disks....




Clutch slave was toast.

Torque tube was damaged.













Some tell tales on the driveshaft.





Here's all that was left of the pilot bearing:



Notice all the metal powder and that the pilot bearing was evidently bored into by the input shaft coming out of the torque tube:



So I talked to the vette tech and he says that the ONLY thing that could have done all that was the drive shaft being too long. OK, I was skeptical, to say the least. This was a carbon fiber driveshaft from Pfadt. "NO WAY", I thought. But to humor him, I contacted Pfadt and asked them about it. They wanted measurements of course, so I measured the carbon fiber part of the shaft, as they requested. Also had the vette tech measure it, and then took it to a machine shop in the local NAPA store so they could measure it. The drive shaft was 7mm longer than Pfadt said the shaft should be.

Long story short (or shorter, anyway) is that all of these parts got replaced: drive shaft (stock one this time), torque tube, clutch, flywheel, throw-out bearing/clutch master and slave cylinders, and pilot bearing. Pfadt wanted the driveshaft back to measure it themselves, and I requested a refund for the shaft. Granted it was purchased three years ago, but the fact of the matter is that they made a mistake and shipped out the incorrect shaft for my car. Three different shops installed or reinstalled the shaft and drivetrain and Pfadt claims that it is their fault for not measuring the driveshaft. They did wind up sending me a replacement shaft, the correct length this time, but by that time my car was put back together again and I certainly have no intention of tearing apart the drivetrain again, just to put this new shaft in there. So basically I have a $2,000 doorstop right now.

So yeah, THAT was fun.