I am quickly coming to the conclusion that the gear case is leaking. As you can see in this drawing the oil is coming from above. I did a big maintenance stint this Saturday. Replaced the water pump, belt, hoses, coolant and dif fluids. While I had the air cleaner off and the water pump out I removed the alternator. No sign of a leak. It only leaks when it's running. I cleaned everything up with alcohol and put RTV along the edge of the gear case. This morning since it didn't run it was dry as a bone. I drove to work, climbed under and low and behold, oil running in the corner of the alternator bracket and gear cover. It seams the gear cover is leaking up high on the left side only when the engine is running. I did torque those bolts a little more but it didn't help.

Next step... Remove air cleaner, remove alternator, remove water pump. Clean up with solvent and RTV the joint. I'm using Permatex gear oil RTV. The stuff really grabs.

Maybe some day I'll do it right id this doesn't buy some time. Too big of a job for this level of a leak.

The second photo is a picture from another site. I believe the leak is from the area of the gear case where the oil pump is.

 

I have not see that happen.

While the blocks of the 6.7 and 5.9 are common, you might want to try in the 5.9 section for a little more exposure.