@
DoomsdayJesus
Sorry to chip in so late, just saw this thread.
My transmission was grinding in 5th gear at normal motorway speeds. Anyway by the time I talked to Toyota about it and they wanted the car in I had a track day lined up so I said I would come after the weekend.
Funny thing is, after taking it to the track the problem fixed itself.
Still using factory fill, but yeah, the transmission is now wonderful. Not saying this would work for you, but in my case giving it a proper thrash seems to have resolved the issue for me.
Good luck getting it sorted.