I just left my local Ford dealer after they refused to service my F-53 ford mo ho on the grounds that it was too big. Now ths is not a old time Mom and Pop dealer, this is a dealer with multipal brand...
I had a similar problem with a Chevy 454 in my motorhome which was still under warranty. Chevy just referred me to the closest GMC and all was handled. I would think the Ford dealer could either refer you to Ford Truck service or call Ford and find an authorized contract facility for warranty service.