I'm the original owner of an 03 G35 Coupe w/ 6MT. I had my original transmission replaced with the updated OEM transmission about five (5) years ago. Just recently, I noticed some gear grinding noise when I shift. The noise is intermittent that's happening in different gears at different shift times. The car seems fine when I engage and disengage the clutch. It's when I switch gears and the initial entry into the new gear is when the noise happens. Has anyone experienced this noise? Thanks for taking the time to read and reply.

 

Check your fluid color, etc. but a posted video w/ a camera and a better quality microphone would help us diagnose your issue. Does the grinding noise delay shifting, what gears is it harshest?