Diesel engine massive oil leak from breather tube.

The other day when my wife got home, I noticed an oil spot under the running board on the passengers side of my 2002 Chev. 2500HD 6.6 diesel truck. I ran my hand under it and it was soaked with engine oil. Upon further investigation, I found that the complete under side of the truck was dripping oil. After it cooled down, I took off the rock guard under the front and the only place I saw that could be the origin was the breather tube from the separator on the front right of the engine. My question is has anyone experienced possibly a foaming problem with the engine oil to where the separator is not able to separate the oil and air thus pumping oil out the breather tube? That's the only thing I can figure happened. After clean up, I added one quart of oil (that's all it took) and started it but didn't detect any oil leaks at all. I don't recall what brand oil it is, but it wasn't chevron delo 400, which is the only oil that's been run in it since it was new. It has 67,000 miles on it by the way.