Rattling sound when in neutral. Goes away when I press the clutch. Gears go in with no grinding, vibration when going around 60 mph. 2006 G35 Coupe with 123,768 miles. Is it the throw out bearings?

 

Do you have the stock flywheel or are you running a lightweight one?

 

Car is stock

 

Input shaft bearing

 

Do you know if it's still the original clutch from the factory?

Does it do the vibration in all gears just like you said it does @ 60 MPH (presumably in 6th)?

5th gear is the 1:1 gear. See if it also does it in 5th gear when moving at 60 MPH, or when in 5th gear when going 46-50 MPH. In 5th gear @ 47MPH, your transmission input shaft speed would be the same as it is in 6th gear @ 60 MPH. Sometimes a worn pilot bearing for the clutch can cause strange noises like this but often won't do so when you are in the 1:1 gear because it's a straight pass through the tranny without much side-to-side force or strain on that bearing. Then see if it does it in 4th gear at around 38 MPH.

Do you still get the vibration at 60 MPH if you push the clutch in while at that speed?