Well, did you read the links I give to you? I'll bet you don't

In order to accomodate the front gear on 3mm shaft just drill that gear with something like 2.97mm and put it on JBWeld.
The other end of the rod - just make a notch on the rod with exacto knife and rear gear will be happy.

I think teflon gears are ok... just make sure that mesh main gear/tail drive shaft gear is not too tight and not too loose.