That's my point, you don't need to! Just buy and build 2 front axles exactly the same. When you mount them to the chassis with the pinions pointing at eachother(so you can connect the driveshafts to the same transmission) the tires will be spinning the right way. If you try to reverse the one axle's rotation, you will be screwing things up, making it turn the WRONG way.
Do you have access to any solid axle truck to look at? Like an SCX10, AX10, Losi crawler, TLT-1, TXT-1, Juggernaut, etc? If so, take a good close look at the axles. On the Tamiyas, the axles are exactly the same front and rear. On the Axials, Losi, etc the center part of the axles are the same, it's just the outer hub area that's different between front and rear.
Try to keep up again, the transmission in the center of the truck spins the driveshafts. Both the front and rear driveshafts spin the same direction, because they are locked together inside the transmission.(let's just say from driver's side-over the top-to passenger side). Now imagine you are looking at the front axle from the middle of the truck; the driveshaft is rotating clockwise to make the front tires rotate forward. turn around and look at the rear axle; the driveshaft spins counterclockwise to make the tires rotate forward.
Bottom line: buy two front axles and build them exactly the same, you will be fine. It will work the way you want it to without any special consideration. Don't beleive me or still don't think it will work? Drop the hobby and take up knitting or something... LOL!
