Stock 08 smokes?

[Preems14]

I just picked up an 08 f350 that is completely stock except for 35's, and under mid to full throttle it smokes until it builds boost? I have seen hundreds of the 6.4s around that are probably stock and there is no soot in the exhaust pipe, they are completely clean and mines full of soot. The truck has 100000km and hasn't had any problems. So i took my truck on its first journey about a 400km round trip towing a 14 foot enclosed with 3 dirtbikes in it. it towed fine for the first 80 kms(also burned 1/4 tank in 80km) then it went to idle, while at highway speed, and lost all power. When i stopped it revved up to about 1500 and would stay there till i touched the brake. so i took off again and it did the same thing in about a minute and then the CEL came on and I parked it. i looked at the exhaust and the rear part of the exhaust pipe was no longer attached to the DPF. I drove it home without the trailer and dont know what to do now? The dealer who sold me the truck said removing the dpf wouldnt void warranty, and i just need to get my truck reliable and maybe a little more power wouldnt hurt either.

[greasltn]

Cracked DPF.

[13_focht]

I've got an 08 with 50,000 miles on it and has smoked under load since new. I also have three other 6.4l from 08 to 10 that don't smoke a bit the dealer says nothing is wrong.