First gear

First gear

(selector lever on position D-3-2)

With the selector lever on one of the three positions, the gearbox functions in the same way and with the same transmission ratio as with the selector lever at position 1, with the only difference that the crownwheel K2 of the front gear set P2 is not locked by the brake B2.

As the torque which acts on the crownwheel K2 is much higher than that acting on the gear train carrier T1, the crownwheel would rotate in an anti-clockwise direction, but the free wheel F1 prevents this rotation, permitting transmission of motion to the gear train carrier and so to the differential relay shaft U, as in the previous case.

However, in this case there is no engine braking effect, as the crownwheel K2 can rotate freely in a clockwise direction, allowing the gear train carrier T1 to rotate at a higher speed than that imposed by the transmission ratio.

Second gear

(selector lever on position D-3-2-1*)

* selected manually (recovery)

The gearbox input shaft E rotates in a clockwise direction.

The crownwheel K1 is coupled to the input shaft E by the engagement of the multiple disc clutch C1, clutch carrier drum D and clutch C3 (already engaged with N or P selected).

The clutch C3 locks the free wheel F0.

The sun gear S1 is locked to the gearbox casing by the engagement of the band brake B1.

The planet gears ST1, driven by the crownwheel K1 of the epicyclic gear set P1, rotate in a clockwise direction, shifting onto the locked sun gear S1; they then transmit motion in a clockwise direction to the gear train carrier T1 and the gear I1 coupled to it.

The gear I1 transmits motion to the wheels via the gear I2 and the differential relay shaft.