Originally Posted by
CraigM
I sanded the gears until they were completely flat with the mould dots gone. The diff feels awesome with kyosho o-rings. From experience using them in tamiya diffs the kyosho orings swell a little initially but then settle down to be light with no leakage
Smooth yes bit they were not as free though. That is why I did not use them. On the Tamiya diffs they were a must for sure, just have not found them to be necessary on the Yokomo differential.