My father and I just bought a DJI Phantom 2 (non vision) with a whole bunch of addons. After a forward fall during landing with the front props hitting the ground, we noticed the front left prop was having trouble with stuttering. After awhile, it would disappear and we could fly as normal. Today, I decided to fly a bit and the front left and right started stuttering again. If you hand spin it while power is on, it will catch and spin normally though there is some whining or grinding noises coming from both motors. The front left feels a little tougher to handspin with power off and the front right feels relatively normal. As far as I know, this has never had any prop guards on it. I believe our problems are crash related but I am totally new to this. The Motors are T-Motor Anti-gravity MN2214. I assume that this is a motor issue and not an ESC one, correct? What are my options?