[TheMachinist]

I think Smallhaul used the drivetrain from a mini rock crawler like a 1/16 Losi or Duratrax on his Tonka's. They are about the right size and would offer plenty of strength and power. Once I find another dump truck to mod that is probably the route I will go, but the RC4WD axle sure looks good and would be a simple install on one of these trucks.