AUTOMATIC TRANSMISSION – ZF 5HP24 DESCRIPTION AND OPERATION The planetary gear train used on the HP transmission comprises three planetary gearsets which together form a compound gear train. The gearset operates in conjunction with the clutches, brakes and freewheel clutch to produce five forward gears and one reverse gear. Planetary Gearset – Exploded View 1 Ring gear 1 2 O-ring 3 Snap ring 4 Planetary gearset 1 5 Planetary gearset 2 6 Planetary gearset 3 7 Snap ring 8 Ring gear 3 9 Intermediate shaft gear 10 Ring gear 2 11 Input shaft gear 12 Needle roller bearing 13 Snap ring
AUTOMATIC TRANSMISSION – ZF HP 44-2-26 DESCRIPTION AND OPERATION The planetary gear train is a single integral assembly which comprises the following components: l Three single planet carrier gearsets connected in series l A single sun gear l A twin sun gear l Three ring gears. Power Flows Operation of the transmission is controlled by the EAT ECU which electrically activates various solenoids to control the transmission gear selection. The sequence of solenoid activation is based on programmed information in the ECU memory and physical transmission operating conditions such as vehicle speed, engine load, throttle position and selector lever position.