PLANETARY GEAR UNIT The planetary gear unit is composed of three sets of planetary gears, three clutches which transmit power to the planetary gears, and four brakes and three one-way clutches which immobilize the planetary carrier and planetary sun gear. Power from the engine transmitted the input shaft via the torque converter is then transmitted to the planetary gears by the operation of the clutches. By operation of the brakes and one-way clutches, either the planetary carrier or the planetary sun gear is immobilized, altering the speed of revolution of the planetary gear unit. Shift change is carried out by altering the combination of clutch and brake operation. Each clutch and brake operates by hydraulic pressure; gear position is decided according to the throttle opening angle and vehicle speed, and shift change automatically occurs. [THIS IS DIAGRAM: Cross-sectional technical drawing showing the planetary gear unit assembly with labeled components including O/D Direct Clutch (C0), 2nd Coast Brake (B1), Forward Clutch (C1), 1st & Reverse Brake (B3), Rear Planetary Carrier, O/D Brake (B0), Direct Clutch (C2), 2nd Brake (B2), Rear Planetary Ring Gear, O/D Input Shaft, O/D Planetary Ring Gear, O/D Planetary Carrier, O/D Planetary Sun Gear, Front Planetary Carrier, Front & Rear Planetary Sun Gear, Output Shaft, O/D One-Way Clutch (F0), Input Shaft, Front Planetary Ring Gear, No. 1 One-Way Clutch (F1), No. 2 One-Way Clutch (F2)] A72157 OPERATION OF EACH ELEMENT NOMENCLATURE | OPERATION O/D Direct Clutch (C0) | Connects overdrive sun gear and overdrive carrier O/D Brake (B0) | Prevents overdrive sun gear from turning either clockwise or counterclockwise O/D One-Way Clutch (F0) | When transmission is being driven by engine, connects overdrive sun gear and overdrive carrier Forward Clutch (C1) | Connects input shaft and front planetary ring gear Direct Clutch (C2) | Connects input shaft and front & rear planetary sun gear 2nd Coast Brake (B1) | Prevents front & rear planetary sun gear from turning clockwise or counterclockwise 2nd Brake (B2) | Prevents outer race of F1 from turning either clockwise or counterclockwise, thus preventing front & rear planetary sun gear from turning counterclockwise 1st & Reverse Brake (B3) | Prevents rear planetary carrier from turning either clockwise or counterclockwise No. 1 One-Way Clutch (F1) | When B2 is operating, prevents front & rear planetary sun gear from turning counterclockwise No. 2 One-Way Clutch (F2) | Prevents rear planetary carrier from turning counterclockwise OPERATING CONDITIONS FOR EACH GEAR (See page AT-12)