My sisters 5.4L Expedition was leaking like a sieve... OIL EVERYWHERE! So I crawled up under there and cleaned the area off and could see very well where the leak was coming from.
Called up Ford and talked to the guy, he said he knew exactly what I was talking about and that this is a frequent problem with both the 5.4 and 4.6! The part # is F6AZ*6840*BA and it was only 7.52 for the gasket... after pulling the part You could see exactly what the problem was. The old gasket is on the left and the new one is on the right... You can see that the raised area of the gasket is completely squished flat!!!
So it took all of about 30 minutes to actually replace the part.. not bad at all you will need a 3/8 ratchet, a 3/8 swivel, and a foot long extension. The bolts are all 10mm (I used a deep well.. it worked best since the bolts are kind of hidden) You WILL need to drain the antifreeze (I just drained them into a bucket - then dumped it back in when I got done) but you DON'T have to drain the oil.. all the oil drains back into the pan and the only oil spillage you might come up against is when you spin off the filter.
These next 2 are just pics of the adapter part for reference so that you can see where the bolt locations are..
On this one you can see a sligh casting flaw on the surface but it was ok since it was inside the gasket surface and didn't interfere with the seal at all
I hope this helps someone out on here
Scott.