As title says, there is a strange knocking or rattling noise coming from my transmission.
Background: Shifting into second in my 2016 BRZ makes a strange whirring noise when shifting under higher rpms (~4k+ RPM). This strange noise continued for a while as I figured it was just some wear noise despite the vehicle only having about 16k miles at first notice of the noise. I showed this noise to a more advanced friend and he stated it sounds like a faulty synchro.
Just last week as I was travelling down a 55 MPH highway, this noise became very evident. Strangely enough, the noise was only present when in 2nd, 4th, or 6th gear. 1st, 3rd, and 5th made no noise. I drove the vehicle the other day and attempted to replicate the noise with no success. The vehicle drove in a standard manner.
Below I have linked a google Drive file that is a 50 second clip of the noise. Alongside the noise, there is a rattling can; however, I am sure you all will be able to tell the difference as it is quite apparent. Any suggestions as to what this could be would be very appreciated. I am taking the vehicle tomorrow to the dealership for examination.
https://drive.google.com/open?id=1NB...uDWfWCjEK02Gld