My extruders on the Flashforge Dreamer printer don’t work. I have unclogged them and can even insert the filament into the nozzle when heated enough, so it’s not clogged. I believe the motor that pushes the filament is broken. How do it fix this, if possible?

Have you checked to see if the set screw for the feed gear in the extruder is perhaps loose or plugged or damaged? But alas, I happen to have a manual, hope this helps.
flashforge_after-sales_service_manual.pdf (7.66 MB)