sounds like a possibility to me! how bout low clutch master cylender fluid? Checked that?? I noticed a huge difference in the way my trans shifted when i replaced my master and slave and rubber line. Shifts like a new trans now!
its not low cluch master cylender its low fluid in your master cylender. Open your hood, and look back in the right hand corner. You will see to clear resivors with break fluid in them. The bigger one further to the right is your break master cylender, the small one is the clutch master cylender. The slave cylender is on the transmission. Check the levels on both of them. There are lines on the sides indicating low and high marks. If your clutch fluid is low that means you probably have a leak somewhere. Most comon clutch hydraulic leaks are from the master cylender leaking or the rubber hose next to the slave cylender.
9/10 it is the 3rd gear synchro is gone. I had the same problem on my black lude...NOTHING fixed it. I put in a new clutch, throw-out bearing, pressure plate, new slave cylinder, lines, you name it. Switched out the tranny...never had it come back.
Just replace the tranny. 300 bucks on e-bay for a nice used one. That's where I got mine.
Don't think its possible the clutch could be causing it. Especially if there is no sign of the clutch hooking up when pedal is depressed. Also if you have gap while releasing the clutch before the clutch begins to hook up don't see how it could be the clutch. That means its fully disengaged. No way for it to be causing the grind in that case. As a test if you are sitting stopped and step on the clutch and are able to move through the gears with no trouble its very unlikely its the clutch.