oil leak
 

I have a 2000 z28 and it has an oil leak. It seems like its coming from the back of the engine, because there are signs of oil on the top of my bellhousing. Is there a sensor or something on the back that can leak? and it also seems like there is grease/oil on the front of the engine that i cant pinpoint where it's coming from. Are there any common leaks in either places?