servo's check out fine , full range and rate of motion on all 3 , and no obvious damage to cases or workings , servo noise seems to be the same , no grinding or rough spots or delay . also , ran it up to just below take of rpm and I can see the movement even on the ground. its a fairly slow rate pulse forward then backward on the nose to tail axis . not seeing any movemnt in the servos but it must be somthing , seems too slow to be rotors or really any of the rotateing parts , but maybe its some sort of harmoic. this one has me stumped. I wonder if I might have a loose bearing or somthing some place , main shaft , or perhaps in one of the blade grips? somthing small thats translateing to a large movement eventualy? or maybe I just damaged part of the 3 in 1 or somthing. its so slow compared to the vibrations I am used to tracking down. in a way its almost creapy , its like the heli is posesed by an old lady rocking on the front porch. what is really strange is it dosen't seem to effect the hover much , I dont have to counter on the sticks to keep it in place , its like it self corrects , or rather self over corrects , just a perfect rocking motion in the air more or less in one spot with normal control inputs to keep in in a hover.