I have a a hitec 5955 that seems to work fine. My issue is that when i turn the servo by hand it feels really rough. I bought the servo used and it was like that when i got it. The reason i say it works fine is because im not sure how it should perform because it was like that when i got it. I have felt other servos like it that feel really smooth. I took the servo apart and the drivetrain seems ok, i think it the motor that actually feels rough. its almost like it has these tiny clicks. what could be the problem?