Noisy actuator

Hi all
I have an 12 inch superking(jaeger)actuator which has developed an annoying squeaking (not quite grating) noise. It still works but I am afraid something may be going amiss internally. Does anyone know if these units need to be lubricated or has anyone experienced similar problems before. Please can anyone explain simply how the actuator works, is it a simple motor which inturn drives gear wheel and the a a worm drive setup?
Cheers for now!