I have a 08 g37 with a 6 speed and an aftermarket stage two clutch and flywheel. I was headed home the other night and a new Mazda rolled up wanting to play. Well we was on the freeway and already rolling pretty good when we started. But it didn't run like the g tobsay the least. Then we slowed down to like third gear and went again. Everything was as it should have been. I ran it on out to sixth gear and like 150. Then on the third time we did it I missed fourth and hit second. The clutch stopped working right then. I went ahead and limped on home. Now everything is like three months old with the clutch. So I got up this morning thinking I might bleed it out but no luck. The fluid that came out was grey looking and I had ran a whole bottle of fluid with no luck. So now I'm kinda thinking that the release bearing assembly might be weak but I'm not sure any thoughts thanks

 

CSC most likely, it's the Achilles heel of 6MT 370/G37's

 

That's all that I can think it could be too. I can hear it moving inside the tranny but I don't think its moving far enough to disengage the clutch. The master cylinder has got to be good because you can still get pressure. Thanks for the reply I won't be back home till the weekend to change it. It shouldn't be that bad of a job just to change it only should it?

 

You sure you didn't over rev the engine?

 

Yes the rev limiter and fuel shut off catches that before it blows. I just don't have a clutch

 

^^Neither of those will still prevent a mechanical over rev due to an incorrect downshift.

Your description is missing detail. "Clutch stopped working" Do you have pedal pressure but no clutch disengagement, is there little to no clutch pedal at all? Is the pedal at the floor on its own. Details will help narrow it down.

 

Sorry about that, the clutch stopped disengaging therefore you couldn't use it to change gears. And was really soft. It kinda felt like it just didn't have enough pedel After I got home and started bleeding it, it never got any better. It was still the the same. But whenever I started it up it got even softer. Any ideas?

 

Probably the CSC. If it gets softer and softer until you lose all pressure, it's your slave cylinder.

 

It never looses all pressure it just gets a lot softer when running

 

Is it spongy? Is the engagement point lower? Was fluid coming out when you were bleeding it?

You could try disconnecting the line that goes to the CSC and pumping the pedal and seeing if fluid comes out. If it doesn't then it's a master cylinder issue.

 

Yes it was spongy and the fluid that comes out was grey instead of clear. I ran a bottle of dot 4 through it and it got clear but didn't work. As for the master it was doing as normal when you opened the nippel fluid came out like always. I bleed it about every 2 to 3 thousand miles anyhow. So I'm pretty sure the master is still good

 

Limped home, can't select other gears, soft pedal? Sounds more like a toasted clutch. However, you're not being very descriptive which makes it difficult to diagnose across the interwebz.