Saturn5

I'm looking for some input on what this clutch noise might be. I don't feel the clutch slipping while driving and when I first start driving it doesn't make the noise, but after a hard blast through the gears, then it makes the noise and is hard to go into gear. Wait a while and drive again and it doesn't make the noise, same as before.
With the car in gear and clutch released, it drives normal.
With the car out of gear and the clutch released, there's no noise.
When I press in the clutch, there's still no noise until I move the shifter into gear and that's when the noise starts. If I pull it back out of gear, the noise slowly stops. If I pull it out of gear and release the clutch, the noise stops immediately. When starting off driving, it makes the noise while in gear with the clutch fully depressed, but as I release the clutch and it starts to grab, the noise stops.

Clutch, flywheel and all clutch hydraulics were all replaced about 3 years ago and have less than 10,000 miles on them. I had a shop do it and it's all "oem replacement" parts. The car is not raced and I don't do burnouts, etc. because I don't want to grenade the stock rear end.
Video of the noise...

Ideas?

dannyual777

Wow! That's a lot of noise!

I've been doing a lot of research on setting up these T56 hydraulic clutches so I'm learning some stuff but I'm not expert. My T56 Magnum is currently under my LS3 swapped Fox body coupe. I've got my neighbor coming over later after church to help me stab the transmission. Anyway, there are measurements that need to be taken to insure that the clutch works properly.

I need to align my bellhousing because all of it is brand new but this isn't a measurement that you would've needed to do.

In your case, the one measurement that should've been done was to check to see if your new clutch required any shims. If your clutch clearance is too great like mine (.42 inch! should be about .25" maximum) then the clutch may not completely release with the pedal pushed in. I need to shim my slave cylinder about .2". If the clearance was a little too tight to begin with, then as the clutch wears, the clearance gets less and less and eventually the slave cylinder is touching the pressure plate fingers even with the clutch pedal released.

On the other hand, maybe you've got something going on with your clutch master cylinder or the slave itself. I'm just throwing some stuff out there hoping that someone else will chime in to get this conversation going.

Saturn5

Thanks for the reply. I purchased a set of clutch shims and gave them to the shop along with instructions on how to measure the clearances when they did the clutch replacement. They said they measured and none were needed, and it's driven fine for 5-10k miles over the last 3 years. I believe something recent has changed. I do have a slight oil leak and have wondered if I might have oil contamination on the clutch disc. (I had the rear main seal replaced while the tranny was out for the clutch), but I can't tell where the oil is leaking from and I don't feel any slippage in the clutch. It may end up having to R&R the transmission to check everything out regardless, but I was hoping someone might recognize the sound and be able to give me an idea what to look for.

Could it be something internal to the transmission itself? Car has 160,000 miles and the 4th gear synchro has been getting a bit lazy - I have to shift a bit slower going into 4th to keep it from grinding. That said, the noise is the same no matter what gear I shift into. You can't see in the video but you might be able to hear I run it through the gears as one point and there's very little change in the noise itself.

The car needs some work, and if I could get it driving like it did when it was new, I wouldn't mind spending the money. I just don't want to keep dumping buckets of money into it if it's still not going to be right. (had the rear end rebuilt 2 years ago and it's still noisy as hell and I'm told that's "normal.")

Saturn5

I never did post a follow-up on my clutch noise. I took it to a local speed shop that specializes in modern GM vehicles and let them look at it rather than go back to my regular garage. Turned out the clutch disc fractured. Not sure when or how it happened. I've never had the car on the track and I run stock size tires, but I do blast through the gears from time to time. My guess is it was faulty to begin with. You can tell from the friction material the clutch had hardly any wear. It was just over a year old, so warranty had expired. I had it replaced with an LS7 setup and all is well. Oh, and apparently my previous garage didn't measure the clearances to properly shim the clutch. That 4th gear "synchro grind" that I had has amazingly disappeared with a properly functioning clutch installed. Go figure.


So now I've just been enjoying driving the car again. Time to start running the numbers on whether I want to keep it long term and possibly do some bigger upgrades, or consider selling it while it's in good shape for something newer.