Help needed. Not very educated in rc yet or gears at all. I just replaced my spur gear and motor mount in my big rock. Took it out the last couole days. Almost 2 full packs thru it and decent but never full speed. (Not enough room at home.) Plus really taking it very easy. Checking my work. It seemed to sound like the motor spinning faster than the truck going. Almost too high pitched. Runs great. Also the normal whine of a electric rc sounds a bit fuzzy sometimes. Let me know of I need to reword