So, I was just fixing the Rustler 4x4, and I realized that I didn't have any spare rear hub carriers. So, I got to thinking. I had some spare Tekno hub carriers for my slash 2wd, and i said what the heck. I grabbed a spare front driveshaft for the rusty 4x4 and boom. it fit! all I had to do was swap out the outer bearing as it is for a 6mm axle shaft with a bearing that holds the front diff pinion gear. slapped that bad boy on and boom it's a rear axle assembly. So now, if you are sick of having to buy rears and fronts and just want to keep one type, that's a way to do it! I'll update you with pics in the morning!