Speaking of which, one of the issues I had was that the opening for the motor was too small. it was my fault not double checking my dimensions.
It was a pretty easy fix with a grinding bit.
the other issue was that I make the skid to the exact dimensions of the SCX10 skid. well it's injected molded plastic, this is layered Nylon. and in order to get a clean interior for the gears I had to position the part on the machine in such a way the layers went across the screw holes resulting in a crack when I assembled the lower links.
the cool thing is it's reparable.
I first notched the crack
then I chucked a piece of the raw material in a dremmel
and welded the crack shut with friction.
Then cleaned the face with a razor
I may revise the part to be thicker in that area if I continue to have problems.