Taz6 Z-Axis Lead Screw Binding - Difficult to turn!

So I have had a bunch of nice prints for a while. Even printed a new Y-axis idler because there was a non OE one on it and it was tearing apart! All my prints have come out fine until today! I went out and at about 1.5" up a print the layers started crushing together and the z-axis was bound. Stopped print, re-leveled the z-axis started another one… same issue. So i put tape flags on the lead screws this time. While running the print the left lead screw was lagging behind and sometimes not turning as much as the right side. So I shut her down and checked them out. The right one spins VERY easily, can spin it with just the friction from 1 finger. However, the left one is much more difficult to spin! I looked online and tried loosening the spring coupler and seeing if the lead screw would move up and it doesn’t. It seems to be seated in the correct location. It is the rod or the Z carriage… I loosened the spring coupler a lot and just the Z lead screw is difficult to turn so its not a motor issue.
I was thinking of tearing apart the z-axis carriage and cleaning everything up. Is there a replacement threaded nut in that Z carriage? I couldn’t find anything except the carriages themselves but i don’t know whats inside them to grab the threads.
Any tips on taking it off? I was thinking of pulling the X-axis rods out and to the right to free the left carriage then removing the top plate and winding the carriage all the way up the rod by hand… I guess. lol

Thanks to anyone who can help here!

Craig G

Ok I THINK I may have found the issue…
I was going to pull the Z-screw out of the carriage to see ho tight it was and if it was binding… I put my hex wrench and barley rotated it and it popped right out!! It was SO loose that it was barely holding on. I put the scew it in and just had them both touching the top of the carriage nut cap and the rod moved VERY smooth. However, tightening them down bound the nut, so i left it just barely snug. I put a mark on it with silver sharpie so i can see if it moves again, if it does i may get NordLoc washers for it.
Anyone else have similar issues with their z-axis lead screw nuts?

Yes, it has the green flex washer and when that is tightened too hard it will cause the bind. I went through the build docs and they say to be sure not to over tighten