A transaxle system for a golf car, wherein the system comprises a transaxle and a mating interface. The transaxle comprises a plurality of mounting flanges fixedly mountable to at least one axle tube of the golf car, wherein the at least one axle tube houses at least one wheel axle, and the transaxle is operably couplable to the at least one wheel axle. The transaxle additionally comprising a transaxle mounting collar that is fixedly mounted to or integrally formed with a housing of the transaxle. The mating interface is mountable to the transaxle mounting collar, and is structured and operable to have an integrated internal combustion engine-transmission unit of the golf car mounted thereto.