My Grand has a ZF box 8HP70, no dip stick or tube, its a pain to service but to refill its the same as a diff, I just pump it in (3lt) thru the bung on the side, dribbles out, start engine, move thru gears (scary part) then with engine idling pump another litre in till it dribbles out, replace bung and all done. to change the filter its the whole pan that gets changed, since I change mine 3 times to the recommended once in 100K it just gets a half dump of oil at a time..... Pan and filter $150, 4 lts Penrite BMV $80 so buy on special.................. best auto I have ever used, worst I have ever had to do a service on.