My truck is having a sleep over at a North Carolina dealer for the next week due to a coolant leak. There is a coolant line that runs next to the front drive shaft. It looks like it normally would have a bracket that locates it safely beside the transmission, away from the drive shaft. On my truck it looks like the bracket was forgotten, or fell off, allowing the line to contact the spinning shaft.
My truck made it just over 300 miles, 4 hours from home, before the line gave out.

I wish I'd take a pic of that the tech showed me. I did get the part # for those curious. ML3Z-7G071.H
Not having luck finding any diagrams for it but if you get under your Powerboost might want to check it. Look up at the trans after the felt cover/plate? at the driveshaft coupler and see if any trans lines are dangling near it.