I asked a question ealier concerning noise.

I asked a question ealier concerning noise coming from from of vehicle. I herad it again today and lifted the hood. When hood was lifted, rattling and or cranking sound was coming from under the engin cover. Sounds as if somethings loose and hitting the top of engin cover. Sound continues while driving and no interior warning lights have come on. Could this have something to do with too little oil and or trnasmisson fluid?