That is exactly the problem I had on my first tranny.
My second one has 2nd and 3rd grind now so I will be trying Pentosin 75W-80 once I have dealer approval, and then if that doesn't work it will be time for another replacement.
As far as I know, there is still no fix (see links below).
Take yours in and get them to check the tranny fluid - it will have metal shavings in it and that will be the justification they need to replace it.
Good luck!
http://www.ft86club.com/forums/showthread.php?t=16604
http://www.ft86club.com/forums/showthread.php?t=61827
http://www.ft86club.com/forums/showthread.php?t=8437
http://www.ft86club.com/forums/showthread.php?t=31929