Power from the engine is transmitted through the torque converter to the input shaft of the planetary gearbox.
Gear shifting is accomplished by engaging a specific combination of two controls, which changes the output shaft speed.
Elements of a planetary gearbox
1. Forward coupling (C₁) — connects the input shaft and the epicycle of the front planetary row.
2. Direct drive coupling (C₂) — connects the input shaft and solar gears of the front and rear planetary row.
3. Reduction clutch (increasing) planetary row (C₃) — connects the sun gear of the step-down (increasing) planetary gear set and carrier of the step-down gear (increasing) planetary gear set.
4. Engine braking brake in second gear (B ₁) - stops the sun gears of the front and rear planetary rows.
5. Second gear brake (B ₂) - stops the outer ring of the freewheel clutch No.1, thus preventing the sun gear of the front and rear planetary rows from rotating counterclockwise.
6. First gear and reverse brake (B₃) - stops the driver of the rear planetary row.
7. Downshift brake (B ₄) - stops the downshift sun gear (increasing) planetary gear set.
8. Freewheel clutch No.1 (F ₁) - when the second gear brake B ₂ is engaged, it prohibits counterclockwise rotation of the sun gears of the front and rear planetary rows.
9. Freewheel clutch No.2 (F ₂) — prohibits the rear planetary gear carrier from rotating counterclockwise.
10. Downshift freewheel clutch (F ₃) - prevents clockwise rotation of the downshift sun gear (increasing) planetary gear set.
Planetary gear (2WD models)
1 - first gear and reverse brake (V₃),
2 - freewheel clutch No.2 (F ₂),
3 - second gear brake (V₂),
4 - forward clutch (C₁),
5 - brake to ensure engine braking mode in second gear (B ₁),
6 - direct transmission coupling (C₂),
7 - front planetary gear row,
8 - freewheel clutch No.1 (F ₁),
9 - rear planetary gear row,
10 - step-down planetary gear set,
11 - reduction clutch (increasing) planetary series (with₃),
12 - freewheel clutch of the reduction gear (increasing) planetary gear set No.3 (F ₃),
13 - brake of the reduction gear (increasing) planetary series (In₄).