Hello ! I just bought a 04 z06 with a brand new built ls3 and 6 speed transmission and rear end. After driving it for a bit I noticed a sort of faint spinning grinding noise which seems to be coming somewhere under the shifter . It’s there when idling and when foot is on the clutch . It’s not loud at all it’s just enough to bug my paranoid ass!! I’ve seen on other forms it normal for all these cars but i didn’t really notice it on my stock z06 a few years ago . I’ve got a hurst short shift and a McLeod street twin disc clutch .