So I got my 07 6mt G35 coupe about a month ago and when I bought it it had a just gotten a new clutch... since then I drove my 500 city break-in miles and I’ve realized G’s have a lot of clutch chatter with non-OEM flywheels, I am aware of that. However over the past couple days I have noticed a very prominent hissing noice coming from what sounds like the clutch/transmission (something drivetrain related) around 2k-3k rpms when decelerating. It is a very strange noise and only happens in that 2-3k rpm range both accelerating and decelerating but it’s much more noticeable decelerating. It’s almost like a rattling / hissing noise that is quite loud and metallic, you can hear it very well when next to other vehicles or driving past walls or fences. The car feels solid and drives fine, but this noise is quite unnerving... it’s very bad during initial driving like when the engine/trans is cold and gets quieter (but still quite loud) as you drive more. Anybody have ideas on what this could be? I’d appreciate any input some of you G gurus have. Thanks

-A-A-Ron

 

Did you use a new throw out bearing?

 

I’m not sure, the clutch was replaced by a local shop about a week before I bought it. Does that description sound like a throw out bearing? I know there are some general rules that I don’t know like noise when clutch is engaged = this bearing is bad, or noise when clutch is disengaged = this bearing is bad.

 

Ok I missed the part where the sound happens while driving with the clutch released. I would get the car up on jackstands and spin the tires to make sure you don't have a caliper sticking or something like that. Also look for any broken vacuum lines like the one that runs behind the throttle body down to the left valve cover for the PCV system.

 

Its most definitely not brake related, the noise is coming from the center/under the car... it’s turned more into a rattling sound now, don’t think it could be a broken hose but will check anyway. I really think it’s drivetrain related, either a release bearing or a throw out bearing or a pilot bearing/bushing...

 

You're positive it's not the original DMF?

 

No I’m not positive, I guess I assumed that they would have replaced the flywheel but I guess they could’ve just left it. I know you can’t get DMFs machined/resurfaced so they could’ve just I guess saved the money and left it. Don’t know much about the shop that the work was done at... so for all I know they could’ve just reused the old bearings too...