Noise when extruder near the top coming downward

My Taz6 is making a loud noise (z axis) when I run it near the top and then back down. Should I apply lithium to the large screws on both sides or is this something else causing the noise? The rods look clean.

We actually don’t recommend using lithium grease on the threaded rods any more as we found it could dissolve the polymer in the drive nut and cause more problems. I would suggest trying to clean the threaded rod with a clean cloth that won’t leave behind fibers and make sure there isn’t anything caught in the threading of your Z-Axis rods. I know you said it looked clean but it never hurts to be sure.
This might also be a little bit of binding which can occur for a variety of reasons the most common of which is an out of level X-Axis. We have a guide for adjusting the level of the X-Axis here:

Thanks! I’ll give that a try.