The Polini Evolution gear box is the new gear case die-cast in aluminum.
Compared to the original case it can be fitted on the middle shaft bearings and
wheel shaft. It improves the reliability and the performance since the sliding
problems of the two transmission shafts disappear, that on the original case,
slide directly on the cover material. It is supplied with a retainer made of FKM
with inserts in PTFE at low friction coefficient specific to reduce the friction and
improve the sliding of the primary gear and with OR gasket to replace with the
original one to make the servicing easier. The Evolution Gear Box can be fitted
using both the original gear and the longer gears and it allows to fit different
upgraded variators.