Gearbox binding is still present in my m03 if I try to shut the gearbox all the way. I wedge a little 1mm washer at the bottom of the gearcase and it created the necessary space in there to keep the gears free from too much binding... The gears are too big, the pitch is too big, the contact surface is too wide between the gears, and the whole system's rotational mass is huge.... Tamiya needs to rethink the design. My Nikko F1 had a way better running gearbox without bearings at all....
Also, using the carbon gear shafts made it all worse.....