I had an engine light come on last week and ended up at the dealer. They kept it for about 3 days and ended up replacing the cat muffler. I have 14,500 miles on it and going to change the oil again at 7,000 or so. Went into the parts department and told the guy needed some of the Pennzoil for my diesel GC. He came back in with two gallons of white bottle Rotella for diesel. I looked at him and told him I needed the approved Pennzoil synthetic for a diesel GC. He said that is what they are using now. Not handling the Pennzoil anymore. I ask if that was a dealer change or from Jeep/Dodge. He said they are using the Rotella in all the Dodge/Jeep diesels. I reluctantly bought the two gallons. I thought about it over the 4th and decided to take it back since it was not the synthetic grade of Rotella. I use the T6 synthetic in my big International Workstar I tow the toy hauler with. I was just curious if anyone else has been told this or maybe just a dealer deal here in Katy, TX.