I recently purchased a 2005 Silverado 1500 V6 with the 5 speed manual transmission. Ever since I got it, I noticed that when letting off the clutch it would make a slight noise, but nothing to be concerned about. A few days ago I noticed it developed a whine of sorts. As I start driving, it increases with the RPM's so long as the clutch is not pressed. As soon as I get on the clutch to shift gears, it will go away and it's normally not audible while cruising (low rpm's in high gears). I took it in and had a buddy of mine look at it. He noticed a couple of loose bolts and a transmission leak, so we tightened the bolts up and filled up the tranny. As soon as I let off the clutch with the bolts tight, it would make a really loud grinding noise... In order to fix this until we had time to inspect the issue more, we loosed some of the bolts back up and called it a day. Still get the noise when idle and I release the clutch and still get the whining sound. Any help is appreciated!