Metal grinding noise...

So I have a 2002 Tacoma, manual transmission. After starting the engine there is a metal grinding noise. Sounds like it’s coming from the gear box area. After a few minutes of warmup it tends to die down. But when I place it in gear and start driving it gets more pronounced. On the highway the sound gets really high pitched around 65-70 mph. I’ve checked oil and other fluids. All are at full levels.
Has anyone else had this issue?
Any help would be greatly appreciated. Thanks.

 

Does the clutch pedal make a difference in the sound?

 

When pressing the clutch the grinding/winding noise subsides a bit.

 

Have you checked the transmission oil? I suspect it's low, or you've got a transmision on the way out.

 

I haven’t done that. Will definitely look at it. I just had the clutch replaced 2 years ago so I’m hoping it’s not the clutch.
Haven’t thought of transmission oil.