Fyi, im pretty sure the vx diffs are aluminum (i know the plugs are). You really should never have to tighten a fill plug that much, its pretty much there to keep fluids from splashing out and keep dirt from getting in. for some reason people commonly over tighten fill plugs, theres no reason for it. Just hand tighten with a short rachet, thats all it needs. Snug it, then add that little tiny bit past that.