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.
Could elaborate a little on not being able to get it into first? Is is that you have come to a stop and try to shift into first and occasionally it doesn't always want to go right in?
If so, I have the same operational characteristic, just as I have had on most every other manual transmission car I've had in the last 40 years. I just clutch it again and it goes right in.