Here are the parameters--

Leak back by the oil pan, not the drain plug.
Appears to be on the rear side up towards the cabin.
Had the oil changed before ECXC and the place decided to put Synthetic in, instead of regular.
Oil levels not changing, but a persistent leak since the change.
I've found it leaks more after an extended period of time as opposed to short trips.

73,000 miles
2000 XE 4x4

Running theories-
Rear Main Seal Leaking
Oil Pan Gasket
An overfill tube

Any information you can provide would be greatly appreciated in fixing my little problem.

From your description and the fact mine was doing the same thing I would guess Rear Main Seal Leaking, which I had replaced under warranty at 23K on my X. Kind of a bitch of a job so I hope its something simpler?

Mine has had a similar leak. Does it not leak while your truck is resting, but does leak while you are moving? That's the symptoms mine possess. It seems to have been somewhat rectified when they tightened up the torque converter bolts, but I don't see how that could possibly solve the problem. Also, do you have any noticable loss of fluids. I checked everything. Mine's been leaking about a year. No detrimental results. just a dirty underside.

It sounds like the rear main oil seal leak is a common problem. It appears that I have the problem too. Next question: does the repair seem to last any longer than the original seal? I have 80,000 miles on my 2001, and expect to get 200,000 from it, which means that I might have to do this again (after the warranty is up) :o(
Is there a track record?

thanks,

racerecks

Here are the parameters--

Leak back by the oil pan, not the drain plug.
Appears to be on the rear side up towards the cabin.
Had the oil changed before ECXC and the place decided to put Synthetic in, instead of regular.
Oil levels not changing, but a persistent leak since the change.
I've found it leaks more after an extended period of time as opposed to short trips.

73,000 miles
2000 XE 4x4

Running theories-
Rear Main Seal Leaking
Oil Pan Gasket
An overfill tube

Any information you can provide would be greatly appreciated in fixing my little problem.

it's really the half moon seal on the oil pan below the rear main seal you have to remove the tranny to fix

rear main on mine just barilly leaks...but its only when i get in the mud....?