OP - FWIIW, my preference has been Shell Rotella, been using any one of the 3 varieties, crude, blend or full synthetic since day one. Type was dictated by price when I went to buy or time of year. Towing season I tended to use synthetic.
For the past 2 years I have been using the synthetic exclusively because of discounts through Amazon.
Let the Ford dealer change the oil until all of the confusion is cleared up. Cost to fix a engine isn't cheap.
Don
I worked for new car dealers for 20 years, there is no guarantee you are getting any specific oil unless you specified and requested such.
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There is an undisclosed reason that Ford will not recommend ANY oil producers oil currently for their 2017 trucks with the 6.7 . Eventually the Information on the rejection will come out to the market but no one will disclose the reason currently".......
The reason has been out since September, it is a suspected premature wear problem.
This will have to change, Ford cannot demand that end users only use motorcraft oil, because that is the only oil that they approve. If it comes to that Ford will be supplying a lot of free oil. And Ford or Motorcraft do not produce oil.