Noise with oil leaking near fuel tank

Hello All I am new here so please be Gentle, I have a 2008 Ram 1500 2WD.There is a sound like a tire is going bad, a little wap wap noise. I just replaced the tires but the noise is still there. I have a little oil dripping from the rear of the fuel tank. I did not see any fresh oil on the rear-end, any suggestions
Author: Polisram