OK, here's the story. Rebuilt my engine, and shortly after the break in process I noticed an oil leak coming from the rear of the engine (oil was present on the bottom outside of the bellhousing. It never seemed like oil was accumulating inside the bellhousing, as no oil would ever come out that little drain hole. I did notice that a bit of oil had been leaking from the rocker cover gasket at the rear, but after I snugged up the cover bolts, no more oil from there.

I decided to finish the whole break in period (500 miles), before really worrying about it, as it was no a big leak. After driving for say an hour, it would be leaking enough to drip about a quarter sized puddle on the ground. I tried checking the half moon plug, and there didn't really seem to be oil spewing from there. Now that I have the truck in the garage to check my valve clearances, oil change, etc.., I decided to pull the tranny (it needs some work anyway).

When I seperated it, there was oil that had been running from the top down the sides of that plate between the tranny and engine. I could also see oil around that EGR cooler plate on the back of the head. Bellhousing seemed pretty clean, adn so did the clutch and flywheel.







As I thought about it a bit more, the bottom of that half moon seal sits right above that plate on the head. If it was leaking oil, I'm thinking it leaked out the bottom and went around the sides of that cooler plate and down between the bellhousing and engine. I think this may be the source.... and THANKFULLY not the rear main. If it was the rear main, would there have been more of a mess in the bellhousing? Can those half-moon plugs leak that bad to make it look like a rear main leak? Seeing as they're still new, should I replace them, or just take them out and put more sealant on this time?