Yeah heating it up and trying to take out the plug with a larger diameter bit + M12 impact didn't budge the drain plug.So my youngest son and I, just did all the fluids on his Trail 4R. And his front diff did the same. That drain plug does not have a high metal/iron content. The fluid up front was clear and I just pumped it out and refilled with new. After I couldn't budge the drain plug, I heated it up around the plug it with map gas torch and tried that, and that's when the 10mm hex stripped on me. I think I'm gonna order a new plug and tackle that on the next service. Let me know how your efforts go.