03Z06 with 60k miles. Stock powertrain.Autocross car, sees a lot of high RPM in 2nd gear. At idle in neutral or driving down the road in gear I sometimes get this fluttering noise inside and outside of the car. When I press in the clutch, the frequency decreases until it stops. Releasing the clutch brings the noise back. Sometimes I have the noise and sometimes I don't. It almost sounds like something is hanging off the torque Tube and spinning around hitting something. Any ideas?

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Sounds to me like you need a torque tube rebuild. Most likely one of the carrier bearings. I’d plan to do the TT couplers while you’re in there as well since you’ll be dropping the drivetrain anyway.

 

Sounds like one of the coupler is coming apart. When you push in the clutch the tube stops moving that's why the noise goes away.