I have been trying to figure out why my car is louder than most at my track. I've been trying different gears and tightening / loosening gears and lubing things, with no success. It turns out I had a bent motor plate that made the pinion and spur be out of alignment. Looks like a heavy hit to the motor bent the plate. I suppose I should stop crashing and that wouldn't happen again. Now it's one of the quieter cars -- tip to other bad drivers withy noisy cars, like me.