I have been reading a lot about this leak being the HPOP and not the rear main, it sure looks like a rear main though, its a good chunk of oil, nothin to crazy drippin off the gap between the tranny and oil pan/block. here are some pics, help most apperciated!<p> <p>

 

The best thing to do is pull the TC pan and spray Simple Green or Oil Eater in there, then go do the same thing in the valley. There is a drain hole in the back on the passenger side that allows the valley to drain if you have fluid in there. After you soak it down, you can rinse it with low pressure water. Let it drip out and then dry. Now you will be able keep an eye on what is leaking to determine what to look at. You may just have residual oil from an old leak or something like the EBPV actuator leaking.

 

Rear main leaking is not common problem on a 73.l..

 

These guys on here won't steer you wrong. I had the same thing happen to me with my 7.3 with a severe amount of oil running from the back of my pan too. The big red flag popped up over my head saying rear main followed by a few curse words, but I calmed down and got on FTE and the guys here led me to the top of the engine. After some calming words by these guys, some simple green and a pressure washer, turns out it was the "so called" Non serviceable plug leaking. If you contact dieselorings.com for the parts and a little knowledge, that non serviceable port actually is SERVICEABLE. I knew something wasn't jiving when Ford told me that my HPOP wasn't repairable if that plug was leaking and it had to be replaced, then turned around and priced me a new HPOP........but with a core charge....DUH.....If it isn't repairable, then WHY do they want mine back??????

Anyway....Just make sure you have eliminated the topside sources of potential oil leaks before busting into the lower end of your beast. The guys on here can usually save you some time if you listen to them.

 

When I got mine used a few months ago I had the same symptoms you are describing; I thought the same thing about the rear main seal... after doing what these guys suggested I cleaned the valley and started looking for leaks.
I had oil/dirt in the whole valley front to back and was trying to figure it out.
I did not expect it but I actually had two leaks (causing confusion on where the problem was coming from)

- Turns out the HPOP was fine (nothing around the fittings)
- The EBPV was leaking (had to look under the turbo at the back of pedestal to see it. ) There was no oil on the pedestal so I had to look farther back and under the turbo to see it.
- and the Fuel Bowl drain **** valve was leaking fuel under pressure (common issue with the new ultra low sulfur diesel fuel and the older 7.3L o-rings)

Got all my repair parts from Guzzle and RiffRaff Diesel for a good price ~$100. Good guys and good price!