First of all, TR rattle is a total PITA.
If tweaking the TR nut back and forth a bit doesn't help, the fast and quite literally dirty way to remedy it is to inject something into the TR channel, usually about the halfway mark will do.
And dot markers are the perfect place to do so.
I've done this with silicone sealant and white glue.
The latter is more "kosher" way of doing it, but if overdone, it can ruin the neck.
Originally Posted by Bassamatic
Since the truss rod is under fairly high tension...
Can You elaborate a bit?
I don't have Your years of experience, but with the cheapos I've tinkered with, the TR can be totally loose and still there's no relief.
The most common reason IMLE is using an incorrect oil for the FB, the second most common, a refret gone wrong.
Assuming obviously that the neck has been all right at some earlier point
DOA necks weren't uncommon in the 80's when I started out either.
Choosing strings with a higher or lower tension than the current ones and adjusting the TR will alter the TR's resonating frequency, obviously, so that's worth a try as well.