You didn't mention rotation speed or budget . . .
Sorry.
I'm not too worried about the price at the minute. I will save if I have to. I just want to buy a servo that will do the job right the first time
Anything faster than 0.18 sec/60 deg @ 6v will do.
I don't think the sound is coming from the gears. I think it's the motor.
My guess is that it is the coreless motor, but I don't know for sure. Some RC forums seem to think not.
If I didn't have the 5645MG digital servos I probably would have put it down to being digital.
If you listen to this youtube video you should be able to hear the sound I'm talking about:
http://www.youtube.com/watch?v=00E6FMTXF_w&feature=player_embedded#]video-2010-07-31-20-20-22.3gp
The sound I'm talking about is the background hissing noise that turns into a loud buzzing when the robot starts to move.
I have looked at the 5955TG but I'm concerned that I'm going to have the same problem.
changed my min servo speed