There's the "right" way: taking it all apart, using new sleeve and nut, re-checking everything...
then there's the "it's worked 1000 times and all is ok" method of marking the nut, removing, cleaning, and reinstalling the nut with the same thread count as it started with.
You're talking $150-$200 for a shop to the do it the first way, and $10 and some of your time to do it the second way.