one carrier with planet gears at least one sun gear and at least one ring gear a speed varying module is connected in driving relation to the input shaft and in driving relationship to the sun gear or gears of the first planetary assembly the speed varying means may comprise a pair of hydraulic units hydraulically interconnected so that one serves as a pump while the other serves as a motor and vice versa one of the units having a variable stroke and being connected in driving relation to the input shaft the other unit which may have a fixed stroke being connected in driving relation to the sun gear the input shaft is also connectable by a first clutch to a carrier of the first planetary assembly and by a second clutch to a sun gear of the second planetary assembly a brake grounds the first carrier in the first range and in reverse and causes drive to be delivered to the output through a ring gear of the first planetary assembly in a hydrostatic mode the carrier of the second planetary assembly being connected in driving relationship to that ring gear and in all ranges these two elements transmit the drive to the output shaft application_number US 78776777 A description one transmission 10 of this invention has two planetary assemblies 11 and 12 having respective sun gears 13 and 14 respective ring gears 15 and 16 and respective carriers 17 and 18 with respective planet sets.