do a very simple test, take the servo disc out and turn the control on, see any dee dee sound come, if nothing happen, means your servo disc install with wrong teeth, try to adjust it, don't make it too tight. If your servo completely free and still have dee dee sound, means your servo is going to die.
regarding the case of dee dee sound, most happen on a control with HRS mode and using a non digital servo. If using HRS mode with non digital servo, your servo will die very fast. Switch it back to PP mode once set and restart the control unit again