just throwing this out there, I took some threaded rod and put it in the hollow part of the input shaft on the drive shaft, it will add ridgity to the axles. untill you can get better ones. it basically helps keep the plastic from flexing. I alos used this same method with Jato axles it has worked some far and I have a vxl setup on my ride.
The problem with the SCX axles is less the shaft and more the yokes. The plastic heats, stretches, then pops off. It's a continual cycle and once they pop they're done, even if you put them back on, they will pop again in 3 seconds.