Jake02Z28

I work at a Chevy dealer and had 2 of the mechanics look at it, one said it sounded like it was coming from the rear end but after driving it more they both decided it was something in the trans. It isn't a grinding noise or really a squealing noise just a kind of high pitched noise that immediately goes away when it shifts to second but never goes away in first, if I put it in first the noise gets louder with higher RPM's. The trans was serviced about 20k miles ago, fluid level is fine and the car still shifts perfect the noise is just annoying.

Just trying to get some more feedback on here seeing if maybe its a common issue. Thanks.