[RCP57]

I was super disappointed with how easy these trucks get stuck last year when I got mine. Coming from all 1/10 scale equipment that is WAY heavier and runs tires nearly twice the size, I guess I should have known but I was still like WTF? Anyway, at the urging of some friends I locked the rear axle to try it and it works much better. I just used hot glue and it is holding up fine so far, the best part being that with greasy gears the glue doesn't stick. It cools and takes the shape of the teeth but the pieces just come out when you take apart the diff without any fuss(I didn't have spare spider gears to use). Chaseracer has both axles locked permanently in his Autocar dump truck and it still steers fine loaded on dirt. I will be locking the front tandem in both my trucks too in the near future just to try it. My Hayes also gets better traction than my KH because it has my own springs and the shocks removed. Like Rob said, if you tighten everything up properly it won't articulate.

I also had the same issue as Mario with a smaller pinion I swapped on. I had to shim the motor back for clearance so that the set screw didn't hit the driven gear. Luckily for me I remembered his experience first and shimmed the motor prior to running it. May not be your issue but it's worth a look.