yea IDK why its so hard to find, went looking for it at wally world and found an empty spot in the shelves where it probably should have been in between HD diesel oil and all the gasser oils. settled for buying pennzoil euro L online since it said it would be here today.... of course the single quart bottle is the one that not going to be here till next week sometime. its killing me to have it sitting there doing nothing.Dexos 2 was designed to protect the DPF and to keep the soot in the oil from forming sludge. A drain and refill with Dexos 2 should be all you need. I would not change the filter just for the cup that is left in there. Most people don't even know that Dexos 2 exists. You can get it from any GM dealership but it's very expensive. I buy Mobil 1 or Castrol from Amazon. Because no one carries it on the West coast.
Castrol 03559 Edge 5W-30 C3 Advanced Full Synthetic Motor Oil, 5 Quart $24.47