Help...truggy doesn't go...

[Big House]

Good folks, I finally got my Mayham St up and functional but when I took it out, gave it a little throttle input, it really did not move. I put my foot in from of it and although the center diff was spinning, nothing was happening in the rear. Now just a few days ago I was cutting grass with it. Could I have killed the diffs in one run? I don't know the condition of them before I run a 1520 with 20 volts through them so what might my replacement options be for replacement?