Were you using the stock front bearing hub? or the Graphite ones?
The main reason i am asking is i've seen the pins disapear on the yok DCJs, and the tamiya's have pin retainers.
Unless someone has added a retainer on the yok DCJs? Maybe a piece of shrink wrap? or is that not even nearly strong enough?
I put a washer of 5x0.5m behind the pin on all 4 wheels to remove all of the slop/slack, i wonder if that can help with your binding issue...