Hi Zak, First off, what year 300 we talking about here ? Second, I seriously doubt whether a significant oil leak could occur from the rear of the pan, and NOT be the rear main. Of course anything IS possible, but sounds doubtful. Before launching into repair, I would suggest cleaning off the affected area of all oil residue carefully with a couple cans of brake cleaner . Then, go to NAPA, buy a small jar of oil dye, and dump it in... run the engine a little, just enough to get things to start leaking, and examine the area with a UV light . The source of the leak should be quite apparent with the dye in the oil. If it's the seal, there will be oil clearly visible ABOVE the line where the oil pan meets the block. John