How did I kill my servo?

No,only thing set was trim.The Mamba monster combo,lipo battery & the servo where all new & it was the first time I ran that stuff.What confuses me is that it would cut out & coast(no steering & speed).I would have the radio trigger at full reverse & It would get zero response fromit until it stopped moving & then it be fine again.This only happened with the Hitec servo & now everything runs fine with the stock Traxxas servos