I was standing at a red light today and noticed a wierd vibrating-type sound. Turned the radio off, knocked the car into neutral and noise disappeared. Back into drive, the noise resumes. Any ideas?

 

How badly does your engine move at idle? It's possible that engine vibrations are being transmitted to the driveline in gear.

 

check your motor mounts

 

pratch - not sure what you mean when you ask how much my engine moves??
ronin22357 - where exactly are my motor mounts and how much approx would new ones cost?

Also, could it be the tranny??

 

eshe odin rysski s maximoi..O_O

 

By moves I meant overall vibration while idling (pop the hood) as mentioned by ronin - I was referring to how well the engine is mounted.

I'm a relative newbie to Maxima work, but have worked on my rotary-engined car for 12 years now. Similar thought processes apply to both

As for how much - check to make sure they're properly tightened and that the bushings aren't worn too much. You shouldn't have to replace them wholesale unless they're really bad.