Never mind the fact
That I spent countless hours attempting to bring the motor back to life in one of my d4s, and ended up having to SWAP THE MOTOR for a less worn out one, and spent even more time tearing it down to the armature frame 
so between what I have learned and what I have taught myself, I now have a nearly pristine D4 SE that runs like it just rolled out of the factory. I am the last person to show off, but it's gross when people assume.
To the OP, I certainly hope that what I posted earlier did not come off as it's not worth the time to try and get your D4 working correctly, as the motors are serviceable, but in the event that the motor cannot be saved, they are very easy to replace and parts machines are easy to track down.
