This chart illustrates the components and which of the control elements are engaged in each range.
A is the front clutch.
B is the rear clutch.
C is the front band.
D is the rear band.
E is the one-way clutch.
The front clutch is engaged in all forward gears and combines with other elements to provide the required ratios according to selector lever position.
When D is selected the front clutch is engaged and the one-way clutch acts as the reaction member, holding the planet carrier stationary and preventing its rotation in the opposite direction to the input shaft.
Power flow is from the input shaft through the applied front clutch to the primary sun gear which turns in a clockwise direction.
Since the primary sun gear is meshed with the primary pinions, the pinions rotate in an anticlockwise direction and turn the secondary pinions clockwise on their pins, on the locked planet carrier.
The secondary pinions turn the ring gear and the output shaft in a clockwise direction at a reduced ratio and with an increase in torque.
The overall gear reduction in first gear is 2.39: 1.
The secondary sun gear rotates freely in the opposite direction to the primary sun gear.
On overrun, when torque is applied in the reverse direction, the one-way clutch unlocks and allows the planet carrier to rotate.
This means the transmission freewheels and there is no engine braking.
In selector lever position D and also in selector position 2, the front clutch and the front band are applied to obtain second gear.
When the transmission changes up from first to second, the front clutch remains engaged and the front band is applied to lock the secondary sun gear to the case.
The secondary sun gear now provides the reaction member and power flow is from the input shaft through the applied front clutch to the primary sun gear and to the primary pinions.
The anticlockwise rotation of the primary pinions turns the secondary pinions clockwise and since they are in mesh with both the secondary sun gear and the ring gear, the secondary pinions walk around the stationary sun gear and rotate the ring gear in a clockwise direction.
Torque reaction in both drive and overrun conditions is taken by the applied front band which holds in either direction.
The overall gear reduction in second gear is 1.45: 1.
In selector position D, the front and rear clutches are applied to obtain third gear.
When the transmission changes up from second to third the front clutch remains engaged. The front band is disengaged and the rear clutch is applied.
Since both clutches are now applied, the input shaft is now locked to the primary sun gear through the front clutch and to the secondary sun gear through the rear clutch.
With both sun gears locked together and to the input shaft, there can be no relative motion between the gears and the whole gearset rotates as one unit to give a direct drive with a ratio of 1:1.
