Can someone explain to me how old clutch fluid and or leaking cmc's affects how a clutch is released properly or not?

The notchy shifting is coming back for me, i've changed the shifter and lubed it up already. Doesn't seem to be the trans oil. I had the fluid flushed a month ago, seemed to help but the notchiness came back. I suspect it might be a leaking cmc leak (there's black gunk where the rod meets the cylinder but its not like its "leaking (dripping)"

Maybe if I understood the mechanisms of it better, i might go and replace some of these parts/flush out the fluid again.

 

As the master crosses dirty fluid, the disengagement becomes less.

Change the clutch fluid. no need to flush and bleed it. Just suck out the master, clean it ourt with paper towels till spotless, and fill it back up.

Your leak will stop.

 

What do I do with all this gunk on the cmc rod?