Servomotors were motors used in droids to move body parts. They were also used in replacement limbs for beings. Some vehicles such as Imperial Aquatic Terrain Armored Transports, also used servomotors without which the vehicle could not properly function.
A 'Swimmer' AT-AT stationed on the planet Sedri during the Galactic Civil War in the Sedri aquatic Imperial garrison needed a replacement servo motor for use during the Sedrian civil war. The base's commander, Aban, ordered a new motor which was delivered by cargo shuttle along with stormtrooper reinforcements for the base, after which it was installed by technicians. With the servo motor installed the Swimmer was fully functional and deployed during the Siege of the Sun caves during which it attacked the Sedrian city of Fitsay. The vehicle along with it's motor was destroyed during the attack however by a group of rebels whom were aiding the occupants of Fitsay.