My main driver has(d) an 05 Duramax. He blew the engine at 115k only to sink $8500 into the rebuild (this was after GM covering 50%). On July 3rd he was heading out to California with a load of trailers (2, one gooseneck, one pintle hitch, both tilts, Gross load was 24,xxx with truck and trailers).
His transmission temps said to be in check and the truck downshifted on him from 5th to 4th (This was between Seligman, AZ and Kingman, AZ) He began slowing to grab the next exit. Truck shifted hard into 3rd and stayed there. He drove over the road back on to the entrance ramp (all in 3rd) and parked the truck. He got out and the truck was saturated in ATF (as well as my trailers). He popped the hood and the truck ignited (hot turbo + boiling ATF x air = no more duramax) His truck became engulfed in flames and he had enough time to get his suitcase, phone and 3 5 gal cans of diesel out of the back of his truck before it went completely up. His truck was only a shell by the time the FD arrived (My trailers lost some paint but checked out fine structurally and only need some paint/wiring)
Apparently the heat of the ATF in the case was enough to cause the torque convertor to pop, so to speak, and spray its contents on the back of the engine, turbo, etc. He has sinced informed me that this has happened to several other people.