While I have found OrangeTractorTalks to be the most helpful site on Kubotas (especially due to the help of Wolfman) ...there is another site you might visit for RTV issues:
http://www.nettractortalk.com/forums/forumdisplay.php?f=133
Hope this helps.
GeoHorn
http://www.nettractortalk.com/forums/forumdisplay.php?f=133
Hope this helps.
GeoHorn