nagatahawk

I have an mo4m with the alpha body.
so far two practice runs at Tamiya's HG track and to lock ups during first 5 minutes.

Both times I found little pebbles inside the gear box. The first time I forgot the little cover, the second time I think the little rocks got inside thru the optional gear mesh holes in the gear case. I will cover the hoes with tape or shoe goe next time.

Also after i rolled it, the inside output bearing on the left side popped into the gear casel, causing a loose gear mesh with the diff.

Would using orings in the out put cups help eliminate this. or am I doing something wrong?

thanks
wn