How would you fix/find the correct part an oil leak coming from deep up into the engine of 04 Chevy Classic?

I've narrowed it down to coming from the rear of the engine near the Trans axle/transmission. The only reason I know it leaks is because there were no oil leaks on drive way and now there is and I noticed them dripping from my car. It doesn't drip a whole lot, but after sitting a while it does make a hand sized puddle. I need to know if this is a common problem, or if it needs to be fixed right away. I'm very handy with car mechanics. But if it needs the engine removed, I'll just take it to a mechanic. Thanks For The Help...How would you fix/find the correct part an oil leak coming from deep up into the engine of 04 Chevy Classic?
always check your oil till fixed. it sounds like your rear main seal is bad they have a temp. fix at your local autuparts its a oil addative.good luck!!