Hello this would be my first post on 06-current forum. I noticed that my si have this whine like a supercharger whine. (Yes! I did my research for more than a week now and nothing came close than 6th gear whine due to cold air intake upgrade.) In neutral, I hear this minimal sound coming from the transmission. If I press on the clutch it goes away. I did my research on that and ended up to bad input shaft bearing. Now, when I drive the car (4th & 5th gear) I hear this unique sound (like a supercharger) when I press the accelerator. When I shift to 6th gear its the other way around. When I press on the gas it goes away and when I let it go the supercharger whine is back. Could it be related to input shaft bearing or my synchro, gear, pilot bearing is bad? Some say it could be the idle pulley or lsd. Please help me its been bugginf me since this happened. Thanks in advance

 

Mine does this too, but I thought it was gear whine, from the tight mesh on the teeth...

 

I had a bad idler pulley on my 08 and the whine wasn't noticeable till around 4k rpm and went to redline. If you're hearing the whine at idle or at low rpm, I'd say it's probably something else.

 

Agreed... We had this issue too and it was the idle pulley.