rebuilding diffs

[blueb8llz]

im planning on using heavier diff oil on my 3905 emaxx. do i just add the oil or do i regrease the gears with grease too?
also, i have two ripped gaskets and one o-ring. if the case is not the above mentioned, am i reassembling the diff wrong? i'm don't think i'm putting too much or too little oil either and i'm turning the gears before putting the ring gear back on.