hello all once again i need your help with my busted clutch!! turns out the plastic cup had broken on the end of the rod so as i write this its being fixd with araldite

the only thing is, i wonderd if the reason it went was to do with lack of fluid, the Big problem is i just opended the resivoir and it was empty, then i was looking through the users manual and it clearly states
dont take the lid off, now im very worried
so im asking you all is that a major problem? and can i just top the oil up?