The boss's missus has a xf with a borg warner 35 auto. It won't change gears unless you are up it. It sounded like a vacum leak to me but when i had a look there is no vacum line to the gearbox and no solinoid. How do these things change gears is it buy the kickdown cable as it feels seized?

if the kickdown cable is seized that is definately your problem providing you havnt done any damage driving hard with seized cable