I've had a lot of members look at this but no replies, perhaps I have not been clear enough so here is another attempt! As I understand it each gearbox and differential housing has a unique serial number, just like the engine. I have a small owners parts book which shows the approximate position of the serial number' on the gearbox bell housing, and the diff housing' but when I look on my car, I can't see them. I am hoping someone else has taken a phot uder their car, of their serial numbers so that I can see where they are. Hope this clears my request up.