It was overheated pretty badly once, and it probably started the problem with engine oil temp too high. That caused the turbo to overheat. Which caused the bearings to wear, and the seal to give out. Luckily the one that was the worst on mine was the turbine side, so it dumped oil into the exhaust mostly. It smoked really badly on deceleration. It did this for about a month, and I had the crews use it only when they absolutely had to. Well, they ended up sending it from Pearsall to San Antonio (45mi), and the thing threw a belt due to an unrelated problem. I told them to stop, and I would send a person to get them a new truck. They drove it another 13 miles with no belt after I specifically told them not to move another inch. This pretty much did the rest of the damage I think.
When I said "grenade", I really exaggerated a bit. The thrust bearing was completely gone, and the shaft had about 3/8" of end play in it. It ran the compressor into the housing, and i was missing about 3/16" off the outside of the compressor. The turbine side wasn't any better. I was missing a big amount of turbine. The back of the turbine was run into the metal cup in the center, and wore through it. I ended up putting putting a turbo together from used parts. The donor had been through an engine fire, and was in fantastic shape compared to the one I had. All the rubber parts in the donor were burned, but the center part and the turbine and compressor were fine. I used a Beans rebuild kit, and it all went back together just fine.
There is a big chunk of aluminum (compressor) that went through the engine. I ended up replacing all 8 injectors. I also had chunks of thrust bearing in the oil pan. Bits of rings (seals) in the turbo pedestal. Just a lot of bad things going on.
Got it back together a few days ago, and it runs good. It took a few minutes for the new turbo seals to seat. It smoked a little for a couple of minutes. Or it could have been oil in the cylinders after I did the injectors, maybe.
Here's a video you may want to watch.. It is about a 6.0 with a bad turbo.
YouTube - FUBAR 6 0 RUNAWAY - TURBO SEAL FAILURE LEADS TO TOTAL ENGINE DESTRUCTION