Hey guys new to the board just recently bought my G35 on May 31st. 2006 G35 Coupe 6MT. Before I used to hear a rattling noise whenever I turn off my car, now it is consistent every time I turn off my car. It sounds like something is loose or something. I think it has something to do with the transmission just don't know what. Even when I turn the car off and wiggle the stick I hear a sound. I bought it from an Infiniti dealership and I am planning on taking it in. Just wondering if any of you guys had the same problem.

I also smell something from behind.

 

Thats just normal flywheel chatter... This happens to my friend's 05 6MT too, she hates it as well.

 

As said, the flywheel makes the noise as the clutch is engaged when your engine turns off...if you want to avoid the sound, just push in the clutch to disengage it and then let it out once the engine has stopped.
After a while it just becomes habit.