I just got an old Ender 3 for cheap and wanted to replace the crappy extruder with a nicer bowden extruder of my (now) direct drive Kobra Max. When I connect the new stepper, nothing moves. It’s a longer stepper and a different manufacturer. Is the wiring different or VREF wrong or are there other reasons why it wouldn’t move? The driver is good, since the old stepper is still working.

Thanks for any help!