Fiat 1996 Brava Service Manual page 489

Auto transmission and differential Bravo-Btava iggne,
Components and operation
21-27.
Third gear (selector lever on position D-3)
The gearbox input shaft E rotates in a clockwise direction.
The crownwheels K1 and K2 are coupled to the input shaft E by the engagement of the clutch C 1 ,
clutch carrier drum D and the clutches C3 and CO.
The clutch C3 locks the free wheel FO.
The epicyclic gear sets PI (S1 - ST1 - K1) and P2 (S2 - ST2 - ST3 - K2) lock onto each other when
their transmission ratios are different.
The planet gears S T 1 , ST2 and
ST3, locked, drive the gear train
carrier T1 in a clockwise direction
at the same speed as the input
shaft E (ratio 1:1).
The gear 11 transmits motion to the
wheels via the gear 12 and the dif­
ferential relay shaft U.
Fourth gear (selector lever on position D)
The gearbox input shaft E rotates in a clockwise direction.
The crownwheel K2 is coupled to the input shaft E by the engagement of the multiple disc clutch C 1 ,
the clutch carrier drum D and the clutch CO.
The free wheel FO allows the crownwheel K1 to rotate in a clockwise direction.
The sun gear S2 is locked on the gearbox casing by the engagement of the band brake B1.
The planet gears ST2, driven by
the crownwheel K2 via the planet
gears ST3
r
shift onto the locked
sun gear S2, rotating the gear train
carrier T1 in a clockwise direction.
The clockwise shift of the gear
train carrier T1 makes the planet
gears ST2 rotate in a clockwise di­
rection on the locked sun gear S2
and the planet gears ST3 in an an­
ti-clockwise direction.
The anti-clockwise rotation of the
planet gears ST3 on the crown­
wheel K2 achieves a further in­
crease in clockwise rotation of the
gear train carrier T 1 .
The result is that the speed of the
gear train carrier T1 and the gear I I
is higher than that of the driving
crownwheel K2, obtaining 4th gear.
12 Publication no. 506.670/06