the 5th gear is the big one on the top of the shaft in the photo. when used with the little gear (the small one that is on its own in the photo) so you remove the old top shaft and replace it with the on in the picture which has the extra gear on it. Then remove the end nut on the bottom shaft and fit the little gear to complete the 5 gear set up. So you keep the old lower shaft but replace the top one. The casing is bigger because of the extra two gears
Okey, i understand little more. i did take of my gearbox today and check it and i did take some photos to se what you all mean.
Is it this i gone change with that new shaft on the photo?

But that "little gear" you talking about i need to fit it, or change it? Is this end nut in that "house"

Do you understand what i mean?
