the accord V6 tranny is problematic. there has been well documented reports of "something not being up to spec" at the factory when they were produced. if you have a late 99 model, you could easily have the same tranny that's in the 00 and 01's. the 00 and 01's had their drive train warranties extended to 100,000 miles by Honda.
if you're under warranty still, take it in asap and i could bet that they will just replace the entire transmission than try to rebuild it.
do you feel the car slipping out of gears? hopefully it's not a broken wastegate (which was repaired on my car), and you can get a new tranny on the house. :thumbup: