Ok to start.
I'll be totally honest, I generally drive my LGT like I stole it. I've launched it a few times but generally just drive like a dickhead.
It's an '05 stage 2+ (bnr 16g @ 19.5PSI, tmic, AEM intake, ebcs, comp clutch & lw flywheel) w/ 137k
That being said.. The noise in question sounds like a combination of:
whining (not like the normal gear whine)
It happens in any gear, or at say 70mph on the highway no gear.. clutch disengaged or engaged.
I know it's not going to be a cheap fix, and i'll probably do an overhaul on it.
What are your thoughts/idea's?