[BrianG]

While the Muggy is called a MT, it is really built like a truggy. Most MT have the spur/pinion, and tranny, and the diff to reduce ratios. From the pics of the Muggy, there is no tranny, so you lose whatever ratio there. Then, the tires are kinda big. The diameter of the tires actually has a lot to do with gearing. So basically, you have a relatively heavy truck that is geared tall. If you have a high kv motor (like a 7xl or equivalent) it may be trying to do too much with too little gear reduction. The MM should be fine at 100A, but I wonder what kind of currents you are pulling in bursts? Maybe it's too much due to the motor wind coupled with the weight/gearing of the truck?

Or, maybe your batteries are dropping voltage too much under the heavy load? Are you using NiXX or Lipos? If lipos, you can tell if it's an LVC issue by temporarily lowering or disabling the low voltage cutoff. If it operates fine, then you batt voltage is dipping below cutoff when you really gun it. And that may be a wiring, connector, and/or battery issue.