Castle doesn't warranty the MM esc being run in MT's such as the e-maxx and e-revo because of the weight and increase load on the electrical system. I would agree that I would bet it started with tired caps, then the fets when out with a puff. Time for a bigger esc now that they are available. I'd try a refurb MMM, only 100 bones if they still got them and they have full waranty.