Ive been having he same prob, it makes such a racket that it really worries me. Dude at the shop told me to try turning my front locking hubs to 4x4 instead of 2x4, same problem. In 2x4 the front wheels shouldn't be getting ANY sudden torque, but it happens in both settings.

I do notice it happens less frequently when I turn the "Power Mode" button on. I'm still not sure what to make of it. It almost feels like the front wheels are "hopping" for a half a sec when I stomp on the gas from a dead stop.

I too am using mudders, Yokohama Geolanders that are getting pretty thin down the middle. I wonder if they actually DO hop a bit. But shouldn't happen at all if the locking hubs are in 2x4 cuz the fronts shouldnt be getting any power at all in 2x4 if I understand it correctly.

Anyone wanna correct my assumptions?