Assuming you have solved the wiring issues this appears to be a simple Vref issue.  Try turning it up 1//16th-1/8th of a turn and try again.   That motor should have no problem pulling that filament in but for the benefit of other readers, squeeze the tension bearing arm to move it out of the way and then feed the filament by hand past the gear.

Vref solved that issue . Thanks.
but this new motor is making me go crazy. I ll try to use the one on the z axis and put this crazy motor on z and see what happens.

Well friend I think you are looking at the wrong end of the horse.   if you have a wiring problem  a  good possibility it is probably on the board end.   
From what I have read the motor is not considered user repairable and for the cost of replacement not worth sending to a repair depot.

Is the extruder clear of filament. Also I drew a line on my gear to see if it turns.
check the connectors on the  board  try to jog  the extruder. you can swap the extruder with another axis to verify the problem is with the motor or driver.
Tin

i may have spoken too early. Yes the wire was damaged and i also put another motor. Right now without the plastic the motor rotates but when i feed the plastic and force the extruder gear it goes back and forth again and doesn't grab the plastic. I ll put a video in a second. It might be the driver. I ll try to swap the extruder with another axis to see if the driver is the problem.
thanks a lot

Well friend I think you are looking at the wrong end of the horse.   if you have a wiring problem  a  good possibility it is probably on the board end.   
From what I have read the motor is not considered user repairable and for the cost of replacement not worth sending to a repair depot.

Is the extruder clear of filament. Also I drew a line on my gear to see if it turns.
check the connectors on the  board  try to jog  the extruder. you can swap the extruder with another axis to verify the problem is with the motor or driver.
Tin

honestly i did my homework on this. There is a broken cable, one of those 4, and when the extruder stalls i can make it work immediately by changing the position of the cable.
Thanks for the advice. Do you know should i try to take the motor apart and changr the cable or strip the beginning of the cable and add a new one?
new model solidoodle has a socket on the motor too but these sd3 models are bad for repair.

Is the extruder clear of filament. Also I drew a line on my gear to see if it turns.
check the connectors on the  board  try to jog  the extruder. you can swap the extruder with another axis to verify the problem is with the motor or driver.
Tin