I highly doubt your 4.7L oil pan is leaking. Unless it has been resealed before. I've never seen a factory sealed one (either pan), leak. We do see a very very mild weep, at front 3 point (BK2: oil pan, pump block) seal corner.
It's much more likely oil from elsewhere. Rule of thumb. Degrease and clean spotless, all oil off engine (all). Watch for first reassurance, to pinpoint leak(s).
I.E. (2000 4.7L)
- Head covers (retorque to 54 INCH-lbf)
- Oil dipstick O-ring. (replace)
- Timing belt tensioner bolt threads (not sealed during T-belt service). Can you live with, until next Timing belt service!
- Crank seal, if not factory install. Can you live with, until next Timing belt service!
- Cam seals, if not factory install. Can you live with, until next Timing belt service!
- Oil pump O-ring and or rear O-ring, often called remain. (Happens if: engine run too long on cheap oil between changes, run on High Mileage oil, Overheated or prolonged running hot). PCV system not opperting to spec, can result in leaks. We can mitigate these.
The where and why of a leak, and how bad the leak. Dictates course of action!
Can pans be resealed, without pulling engine:
Whereas oil pans, can be removed and resealed, in-suti. It difficult. It also 50/50 chance it will leak in time, between block and upper pan (more so than lower). Why? Any oil on FIPG sealing surfaces, it will not hold. It takes supper care to make sure block, does dip/run/weep oil onto seal surface of block for upper pan. A block right side up, will retain oil on walls, for month or so, once pans off.
If we remove engine, it easy to keep surfaces clean and reseal.
Remove frt diff to do in-situ. Is labor intensive also.
Personally, I pull engine to replace oil pump or it's O-ring. Which requires pulling both oil pans. While out, there are the while in there stuff also. It can get expensive.