Thanks, Danny
I will double check the mounting. I know that I used the rubber grommets. As I said, when I remove the surface the servos are all fine. I am using pretty long servo arms and relatively short control horns in order to get about 50 degrees throw. So any slop at all gets amplified so to speak. For example, the same servo on the aileron never oscillates because the aileron has less moment of inertia I believe.