Massive oil leak...

[Pete1990]

So i have a 07 9400i with a ISX(CM870)
I Had the truck and engine washed today before then i had no issues. I've always had a small front cover leak it wasn't too bad was just cleaning it up as needed. After about 100 miles from getting truck washed i looked behind me and see a shi#t ton of smoke. Pulled over and it was from under the hood i thought i had a fire. The engine is covered in Oil i mean covered the rear is the worse of it. So past the oil cooler there is little to no oil till u get to the back. I Had the truck towed off the interstate as i didnt wanna chance driving it and causing a issue or getting a ticket for the smoke(Not coming out of exhaust). My Question is where is this oil coming from has anyone ever had this happen?