Generally
A newly made 18 tooth speedometer drive without the shaft. You use your old steel shaft that you press free from the broken gear, you do that most easily in a vise.
Press the gear in so that the shaft protrudes 7mm, see one of the pictures above.
The drive is in the speedometer plunger which is threaded into the gearbox on the left side. The speedometer cable is screwed into the plunger.
