> I now see the universal warning on the next page, P40.2a

Neil:

Maybe the attorneys wrote that little box....

It is an interesting problem or question, however.  The
nuts used on the Syncro propshaft are "self-locking," too.
Many advise not reusing them.  But if you google "stover
nut" you'll find that they are re-usable, at least some
number of times.  See, for example:
http://www.fastenermart.com/html/stover-lock-nuts.html
ETKA codes the propshaft nuts as "stover" but not the self-
locking nut you have been writing about; maybe it is a
stover, maybe not.  How many times it has been wrenched off
and on is probably an important consideration.

Of course, if I were advising you with some liability, you
know what I'd say....

Richard