Position D - 4TH Gear

PRIMARY SHAFT (P1, P2):
The input shaft rotates clockwise and C1 couples the input shaft together with the rear planetary train ring gear so that it also rotates clockwise at the input shaft rpm.

C2 couples the sun gear shaft together with the input shaft so that the sun gear shaft rotates clockwise. The inner planetary gears do not rotate.

B2 and F1 prevent the sun gear shaft from rotating counterclockwise. The entire primary shaft (planetary trains P1 and P2) rotates clockwise as a unit.

The driving intermediate gear rotates clockwise at the input shaft rpm.

SECONDARY SHAFT (P3):
The power flow is the same as in position D for 3rd gear, i.e., since the driving intermediate gear rotates clockwise, the driven intermediate gear and the ring gear are driven counterclockwise.

C3 connects the sun gear and the planetary gear carrier together. (F3 permits freewheel mode.) The planetary train ring gear, the planetary gear carrier, the sun gear and the driving final drive gear rotate counterclockwise as a unit.

The driven final drive gear rotates clockwise at higher rpm than in 2nd gear.