For the past month or so. I've noticed that when i shift from 2nd to 3rd at 6500-8000 rpm; it creates a grinding sound. Never when I'm at low rpms. From my nooby knowledge. It should be the syncros correct? (I hope not). If not then what else could it be and what could of been the cause/what can prevent it in the future. Lemme know guys, still new to the whole engine,tranny stuff.

BTW - I got a 98 gsr.

 

Syncros going out.
Don't let it grind much or it'll start doing it at low rpms too.
GM Syncromesh is your best fix, unless you choose to rebuild