modify Tamiya gearbox: Belt driven with reverse

[TURBOdrive]

Hey guys, I Just finish some modify on my Tamiya truck gearbox, belt driven to lower the center of gravity， and change 1st gear into reverse. To make the truck more like the real one. But after that I realized that it will be better if I put one-way bearing in the belt wheel to let it run more like an engine.
The reason I add reverse is I will design disck brake on my Cascadia truck, and the brake servo connect the same channel with ESC, so I can't let the motor spin reversely. The final sloution, reverse gear.

I'm in China, I'm not sure if you can read the picture in the attachment.