Help gearbox noise!!!

[Castlo]

My 2010 ve ss manual with tremec tr6060 is making a weird metallic sorta noise only sometimes when I downshift and rev match, clutch all the way to the floor, it's happened in all gears.
Going to change gearbox oil to some castrol Dex 3 atf. Thinking maybe the clutch isn't fully disengaging.

Any other opinions? Sorry I can't be much more help on the noise department by the way

 

[MYVESSV8]

could be syncros, but don't put atf back in, penrite progear 70/75 is what a lot of people use