Hello Church I was surprised to read that a dealer was replacing a turbo on an EcoD truck you are considering. I am friends with the son of a dealership owner here in western Pa. that sold quite a few Eco diesels. He and the mechanic that does most of the EcoD work both told me they have never had to replace a turbo on one. My oil has been changed at or before 7,500 miles and I replace the fuel filter at every oil change. We have had issues of asphaltenes getting thru to the engine in this area, my mechanic advised me to change the fuel filter at 10k miles or less and I should have no issues. My truck has only let me down twice, the first was a dislocated tone ring on the flex plate, the second a faulty in tank fuel pump. Both issues were covered by the extended warranty on the drive line. I am very happy with my truck and have only used the Shell Rotella T6 oil my dealer uses in it. Since the dealer is replacing the turbo I would try to get a feel for how well the truck was maintained and used. I know some have used 15w40 oil in their trucks and it will work but the correct oil is a 5w40 full synthetic euro oil like the Rotella T6. since I started changing the fuel filter also at 7,500 miles I have not had a regen cycle occur, I am quite happy with that. Paul