Originally Posted by howardcano

Thanks for the observations, guys. All the pushrods I've seen are hollow for the full length (which I believe is necessary for oil distribution in most engines). Using threaded rod all the way through eliminates any need for forming or machining threads on the axle. The only machining necessary can be done with a Dremel cutoff wheel: remove the ball ends, and add a flat for the set screw on the collar that supports the inner diff plate.

The 6-32 rod was fine the last time I did this, but then again, it wasn't for a 1/8 scale car. Using the 3/8" axle permits use of a larger threaded rod, but then I can't use the 8x12mm bearings between wheel and axle (which I though was a really slick idea).