MM Stalling?

Hey guys, I have a MM 6900 in a XXX-4 I just got done building up and its having some issues its never had before. If you really hammer on the throttle from a dead standstill the motor seems to lock up and have no idea what direction to turn. Even with a small rolling start it will do the same thing. If you slowly (very slowly) roll on the throttle there isnt any issue but the system is more or less rendered useless with the current setup.


I know its geared properly, under geared if anything. Running a matched 6 cell Nimh though Spektrum radio gear so I doubt im getting any hits. I ran this same motor/esc in my CRT.5 and it was way too hot of a motor for the truck.. however it never had these issues before. Any ideas on what's going on?


Thanks in advance.