Frozen truss rod?

[stonetone]

My 07 blizzard pearl needed serious relief after a long period of inactivity. And a guitar-building friend and band mate who recently played it wanted to set it up for me. Alas, he ran into an issue with seriously stiff action at the hex nut.

Not being his guitar, he didn't want to muscle it and gave it back. So I tried it out and quickly got to the same point. Pretty sure I could make it move, but desperately don't want to lose that particular neck.

Any suggestions? Thanks y'all.

[renderit]

When I encounter this (and for some reason I see it more on Fenders) I have a tendency to take off the nut and lube the threads with automotive freeze free stuff. I always called it "no nut freeze". It is a paste.

Is yours a nut or the base screw?