2343 is a digital servo. Digital servos often sound like they are loaded when at neutral - as in reality they are loaded. Digital servos are always looking for the exact position - but they basically don't ever get there - so they are always hunting either side of the desired position.
I wouldn't worry unless it is really straining, if it's humming, then i'd say it's normal. The judder likely suggests worn gears, as this is another example of it hunting for position.
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Matthew White
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