I noticed yesterday when i started my truck that oil was just pouring out of the motor, and looked to be coming from the driver side. I figured oil cooler lines, no big deal. Well, since it was raining i wasnt able to get a good look at anything, so i crawled under there this morning to see if i could at least diagnose the problem before i leave for work. Well, there is oil everywhere down there, the driveshaft, crossover pipe, oil pan, front diff, its all covered.

Following the trail up the driveway that it left when i moved it over quick yesterday, the trail is perfectly inline with the oil drain plug. That doesnt leak, so thats out. When sitting, the front crossmember drips oil that has accumulated on it, alont with the front diff, leaving a large puddle on the ground, which i thought interesting. The trail definately stops right about where the filter housing is, so why is the whole front diff covered in oil? The oil cooler lines at the block are dry, and stay dry up to about the motor mount. I know they leak a bit up front, but thats not where this mess is coming from. Could the filter housing itself cause this much of a leak, in about 5 minutes time it lost probobally 1.5-2 quarts.

I know this all points to oil cooler lines, but they look alright. They are still in the block, and are still clean and dry. The only part of them i cant get to to inspect is where they transition from aluminum to rubber, and i suppose it could be that, but it seems to far forward and to far to the drivers side to match up with the line on the driveway. Anybody have any other ideas? Ill be replacing the lines anyway when i get time, im just seeing if anybody else has any thoughts.

Get some safety glasses, and face shield if you can. Add enough oil to the pan to get it back to a safe level. Then start the truck and see if that helps to show where the leak is. It could be a pin hole in the cooler line spraying oil on other stuff, then running down it making it look like it’s coming from something else. Oh yea go ahead and get some kitty litter and put it under the truck to help make clean up easier.

K2500 has oil filter angle adapter to clear front drive shaft, 1 of 3 o rings in it bad possibly, or spring clips that hold the GM oil lines into the blocks adapter may have let go allowing the ferrule in the adapter to partially dislocate from the block. Also center bolt on adapter may be loose allowing it to leak

Top it off with oil and let us know if any of those are the problem

Voting with T-D. The OEM adapter to allow filter to clear fwd diff is renowned for blowing one or more of the incorporated orings mentioned above.
They should be renewed with OEM quality orings....until remote mounting the filter, which is justified by the problem you're having.
Take a (close) look at the block filter pad surface where the adapter oring seats. On mine the surface was marginal, and the square oring incorporated in the CantonRacingProducts remote adapter i installed dried out a leak.

I found the hole today, a line split right at the motor mount.