[KiaTech]

As long as the replacement oil is 75W90 or similar (not a straight 60W, for example) I can't see much of a problem - or a change. As far as warranty is concerned... when a Forte manual is killed it's from 'speed shifting' and 'grinding gears' and not from poor lubrication. So far I have seen two manuals piled in... both had synchros completely seized. As long as some oil comes out when we drain them, and it's not black and burnt, then warranty will step up for the bill.