A system and method for electronically controlling the displacement of hydraulic pumps, IHTs or HSTs. The IHT and HST includes a hydraulic transmission mounted within the casing that includes a rotatable hydraulic pump in fluid communication with a rotatable hydraulic motor and a moveable swash plate cooperable with the rotatable hydraulic pump for controlling the speed and direction of rotation of the rotatable hydraulic motor. The rotation of the hydraulic motor is used to drive an axle shaft. For controlling the positioning of the swash plate, the transaxle further includes a rotatable trunnion arm coupled to the moveable swash plate. The rotatable trunnion arm extends from the casing and is coupled to a control arm. The control arm is further connected to the electronic actuation drive, which is mounted to the casing and is used to electronically control the rotation of the rotatable control arm to change the orientation of the swash plate and to change the speed and direction of rotation of the rotatable hydraulic motor.