86.5 Nissan 4x4 3.0L 5spd Trans noise.

Ok I have a poblem that is weirding me out my transmission works great in every gear, but it makes a horrible grinding sound. It only happens when I release the clutch, it stops when I press it in. It does not make the sound in 4th and 5th gear or reverse. It makes it when driving in 1st 2nd and 3rd and when I am in neutral. :runaround:
I have no idea what this is and want to know if its something easy or should I take it to a shop or just buy a new trans. If anyone has any suggestions please help me.

i would definitely try replacing the trans fluid first

maybe with thicker stuff too