Rob, if the axle is installed in the car - the casting date is normally in the vertical "webbing" area on the center section. May not been in exactly the same place on every axle. Casting date on the "horizontal" webbing area. See these pics. I can try to take look to verify over the weekend on some of my 341 housings that I have in storage. If my memory is right, you will be on the drivers side, and have to look down from above to see the casting number.