I don't remember where I found this a while ago but I had it in some random DC pics here i forgot about.

Someone modded their dreamcast and took the noisy plastic gears out and made it silent! HAhah I had thought about this but didn't think it was possible, not sure if it will wear on the motor more over time or not but i bet the sizes have to be exact specific to the gear ratios or whatevers haha
Check it out!