Egr cooler plugged or bad egr?

If there is oil. Oil leaks through piston rings..and this will fix only temporary. It will clog doc and dpf again. Most likely you will have to rebuild engine soon. 700k miles is typical now with egr. Egr and soot kills engine much quicker these days.

 

To me this looks like coolant... check your EGR cooler for leakage at the outlet where the rubber connection. If you have any coolant hitting this new aftertreatment, it'll kill it right away

 

Its probably oil mixed with the ash residue that the DPF makes when it burns off the soot build up. You said the turbo was leaking oil on the cold side but it was probably leaking on the hot side to. Also the oil will produce ash when it burns.

 

Definitely something wrong with yours, I believe Cumminskid is right, could be coolant, here is how mine was looking, first time opened in 700,000 miles. This is aftermarket, I installed it at 900k miles when my original was burned inside, this photos I took few months ago, 1.67k miles, I cleaned but was not bad. Another problem is maybe speed and mountains;Pulling in and out of California is tough for motors, lots more incomplete burned fuel , see all the black smoke when the trucks are climbing those hills , maybe is clogging the dpf sooner.
http://imgur.com/a/PFIcb

 

what is a DOC?

 

Part in front of dpf called diesel oxidation catalyst

 

i have the same coolant leak, did you find out were it was coming from.