Ford prefered grade is 10W-30 but there not much full synthetic in there approved list. Most of the brands I have never even heard of. Shell T6 5W-40 is approved but amsoil is not on the list yet amsoil says they meet the standard with their signature series. Which oil are guys using that are on the list and what weight are you putting in going into winter
https://www.fcsdchemicalsandlubricants.com/main/additionalinfo/dieseloilsWSSM2C171F1.pdf
https://www.fcsdchemicalsandlubricants.com/main/additionalinfo/dieseloilsWSSM2C171F1.pdf