I had the same blank look at the Ford Dealer when I went on a fact finder about the V6. Although the chap behind the counter knew loads once we got over the "what's the reg number - it's not a Ford " sketch......
Next time I'll try the Jag dealer.
I wouldn't want to leave gearbox oil in 'forever'. Just remember to make sure you can loosen the level/filler plug before you take the drain plug out. If there isn't one, then there's not much you can do. Without spending loads of time..........
