Reported a burning oil/chemical smell to the Ford service center early August and was told nothing was wrong. 2 days ago same smell appeared accompanied with large amount of smoke while driving. Immediately stopped and found flames behind drivers side front tire in engine. Put out the fire ourselves with fire extinguisher and was towed to nearest Ford service center. Ford states was a mechanical issue with the front differential causing an oil to leak, cause metal shavings, and ignite in flames.