Whistling/Whining under load on highway

[DsmDanielson]

Hey I know I’m not a probationary member and this isn’t my first rodeo, but please excuse me for putting this here. I simply just don’t know where to start and didn’t want it put into the wrong forum. Moderator please move it if necessary. But as the title states, I just got done with my tranny swap; added a Competition clutch stage 2 and a used transmission with 40k miles from past rebuild, new OEM bearing. I shimmed the pivot ball and it everything works great and I’m breaking in the clutch. NOW, on the freeway under load, slight cruise, (basically any gas at all) the car makes a whistling/whining sound. It’s not terribly loud but it’s noticeable. It sounds like mini spooling turbo almost, but from my drivetrain. I’m only hinting towards the transmission because it it only does it when there’s load on the motor while I’m cruising at 70mph+ as I don’t really hear anything at low speeds. Transmission isn’t sticking or extraordinarily notchy, it actually feels good and my motor doesn’t have any leaks and is good condition. It’s not a spun rod bearing (I’d hope) since I don’t hear anything at idle but that’s what the sound sounds like to paint a picture, but only on the freeway. Ideas?

 

[dustyboner]

maybe when the tranny was rebuilt the builder didn't the backlash right.
does it do it in any gear?

 

[DsmDanielson]

No just 5th really at around 2.5k+ rpms

 

[bduran1220]

Check your turbo for shaft play

 

[ishnish]

Are you positive it only does it in 5th gear? What mods are you running?

Have you tried revving the motor to a very steady 2.5k and holding it there to listen for the sound? In neutral I mean.

 

[Eclipsedriver1981]

i had a noise similar before but it was my bov leaking at flange