Thanks for that, I forwarded the link to the Service Manager at my dealership to look into it for me.
The Hallmark Ford Service Manager checked with Ford and they came back stating to absolutely not use the XL18 additive. Apparently, the TSB says not to use any additives. In my case, getting into first gear is my problem. Through the efforts of the Canadian Ford Rep through this forum and probably my Hallmark Ford Service manager, Ford has authorized the replacement of my 1st Gear Synco and/or 1st Gear cluster to see if this will fix my issue. Hopefully, this will solve my issue. Thanks to Ford for having Reps in this forum to help out customers.
Rory S. Brown from Surrey, BC Canada
2019 Mustang Bullitt, 2014 Mustang MCA Edition in Grabber Blue. Previously: 2016 Shelby GT350 in Race Red, 2015 Mustang V6 Competition Orange, 2012 Mustang V6 Premium ProCharged in Black, 2011 Mustang V6 Premium in Red Candy Metallic, and 1979 Mustang Cobra in Bright Red (My 1st New Car)