A transmission comprising: a housing, an input shaft configured to receive torque from a drive unit, an output shaft configured to transmit torque to a load, at least four planetary gearsets (126, 128, 130, 132) arranged between the input shaft and the output shaft, a variable-ratio unit arranged between the input shaft and the output shaft, and at least four clutches (116, 118, 120, 122) arranged between the input shaft and the output shaft, the at least four clutches (116, 118, 120, 122) being selectively engageable in combination with one another to select one of at least four operating modes wherein the variable-ratio unit is configured to output torque from an input of the variable-ratio unit to an output of the variable-ratio unit, wherein the at least four planetary gearsets (126, 128, 130, 132) include a fourth planetary gearset coupled to the input shaft and the variable-ratio unit and a third planetary gearset coupled to the fourth planetary gearset, the variable-ratio unit, and the housing, wherein a ring gear of the fourth planetary gearset is coupled to the input shaft, and a carrier of the fourth planetary gearset is coupled to the input of the variable-ratio unit, wherein a ring gear of the third planetary gearset is coupled to a sun gear of the fourth planetary gearset, a sun gear of the third planetary gearset is coupled to the output of the variable-ratio unit, and a carrier of the third planetary gearset is coupled to the housing, and wherein the at least four planetary gearsets (126, 128, 130, 132) include a second planetary gearset receiving power supplied by the input shaft through one of a first planetary gearset and the fourth planetary gearset of the at least four planetary gearsets (126, 128, 130, 132), the second planetary gearset having a ring gear coupled to the housing, and the first planetary gearset having a sun gear coupled to the input shaft and a ring gear coupled to the output shaft, and wherein the at least four clutches (116, 118, 120, 122) include a fourth clutch engageable to selectively couple a carrier of the fourth planetary gearset to a carrier of the second planetary gearset and a carrier of the first planetary gearset, and the at least four clutches (116, 118, 120, 122) include a second clutch engageable to selectively couple the carrier of the fourth planetary gearset to a sun gear of the second planetary gearset, wherein the at least four clutches (116, 118, 120, 122) include a third clutch engageable to selectively couple a ring gear of the third planetary gearset to the carrier of the second planetary gearset, and a first clutch engageable to selectively couple the ring gear of the third planetary gearset to the sun gear of the second planetary gearset. a housing, an input shaft configured to receive torque from a drive unit, an output shaft configured to transmit torque to a load, at least four planetary gearsets (126, 128, 130, 132) arranged between the input shaft and the output shaft, a variable-ratio unit arranged between the input shaft and the output shaft, and at least four clutches (116, 118, 120, 122) arranged between the input shaft and the output shaft, the at least four clutches (116, 118, 120, 122) being selectively engageable in combination with one another to select one of at least four operating modes wherein the variable-ratio unit is configured to output torque from an input of the variable-ratio unit to an output of the variable-ratio unit, wherein the at least four planetary gearsets (126, 128, 130, 132) include a fourth planetary gearset coupled to the input shaft and the variable-ratio unit and a third planetary gearset coupled to the fourth planetary gearset, the variable-ratio unit, and the housing, wherein a ring gear of the fourth planetary gearset is coupled to the input shaft, and a carrier of the fourth planetary gearset is coupled to the input of the variable-ratio unit, wherein a ring gear of the third planetary gearset is coupled to a sun gear of the fourth planetary gearset, a sun gear of the third planetary gearset is coupled to the output of the variable-ratio unit, and a carrier of the third planetary gearset is coupled to the housing, and wherein the at least four planetary gearsets (126, 128, 130, 132) include a second planetary gearset receiving power supplied by the input shaft through one of a first planetary gearset and the fourth planetary gearset of the at least four planetary gearsets (126, 128, 130, 132), the second planetary gearset having a ring gear coupled to the housing, and the first planetary gearset having a sun gear coupled to the input shaft and a ring gear coupled to the output shaft, and wherein the at least four clutches (116, 118, 120, 122) include a fourth clutch engageable to selectively couple a carrier of the fourth planetary gearset to a carrier of the second planetary gearset and a carrier of the first planetary gearset, and the at least four clutches (116, 118, 120, 122) include a second clutch engageable to selectively couple the carrier of the fourth planetary gearset to a sun gear of the second planetary gearset, wherein the at least four clutches (116, 118, 120, 122) include a third clutch engageable to selectively couple a ring gear of the third planetary gearset to the carrier of the second planetary gearset, and a first clutch engageable to selectively couple the ring gear of the third planetary gearset to the sun gear of the second planetary gearset.