there are 4 places for an oil leak.
1) Oil Cooler. If the stains or drops are in the vicinity of the cooler, highly likely, oil cooler gasket/o-ring is the issue
2) if the bottom of the oil pan, front and/or back, is coated with film of oil, the oil pan gasket is the problem
3) if there is oil droplets on the center/bottom of the bellhousing, the problem could be either the rear main seal or the rear engine cover porosity issue........or BOTH.