sounds to me like you may have your damp and gain set too hard on the gecko's. I made the same mistake, after softening up on both to quiet the motors humming back to very faint, then things got better. you didn't say which mach your using i'll assume 3. i've got vel @ 135 and accel @ 12 presently. But first ! your gain and damping must be set proper for this to work, how i understand this is, high gain with high damping make the motor tight and it will fight itself to do what it is told to do. You loose NO torque by backing off of gain and damping, you gain control ! if it is noisy will sitting static then it is tight, back off and noise will subside then, drive it in short back and forth runs (jog) and listen to it, tune it for quiet and smooth motion. I found as Aaron told me that with a little practice it'll all make sense and you'll too become an expert ! using an oscilloscope to do this is ideal, but not necessary and to use osc you'd have to remove the gecko cover to get to the hook up pin, unless there is another way, i did it by ear and it runs slick and quiet, I'd also insure that during tuning you insure your not too tight with the gib adjustments so that what you are hearing is the drive true ! Like Tim Allen, I like more power and thought that more gain/damp = more power ! oooh oooh ! WRONG !
Don
IH v-3 early model owner