Quoted from robbiedoo:
So spray the motor?
Like... in the holes? Yes, I'm a noob...
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I agree with Marc. Kim will fix the motor and gearbox. One thing that you might want to try is instead of spraying in that hole that you listed, which is where the magnets and wiring are, you might want to take a toothpick with about a drop of lightweight oil and put it at the rear of the motor where the shaft sticks through the bushing and at the front where the shaft comes through. Those low-voltage DC motors will squeak at those bearing points.
I had a somewhat similar squeak happening with a MM drawbridge motor (and the motor was lifting the drawbridge slower than it should). I put a drop of radio-control engine "after-run" oil on both those points and the motor quieted right down. Sewing machine oil or an oil with teflon in it would work well too but the trick is to use as little as possible on both those points.