Ducati Diavel Workshop Manual page 816

Crankcase assembly: crankcase halves
Note
When refitting used components, before installing the gearbox assembly in the crankcase half, make sure that the inner
races (C) of the gearbox shaft bearings are fitted into the correct bearings and have not been left on the shafts.
Match gearbox shafts, fit the shims and fit them to the clutch-side crankcase half.
Note
A table and a list of the gearbox components appear in Sect. 9 - 7.2,
Insert the forks of 1 st - 4 th and 2 nd - 3 rd speed (D) in the corresponding sliding slots of the secondary shaft driven gears
and insert the pin (G) in the forks: the two forks must be fitted with the number that indicates the gear facing upwards.
Reassembly of the gearbox shafts.