during a print i noticed a clicking sound i noticed the "feeder gear" (sorry dont know the actual name of the part, see pic below ) slipping. took some canned air to it to get rid of most of the shavings and also tried using different rolls of filaments. i also noticed some black gunk on the teeth of the gear itself anyone have any tips on removing this gear? i loosened the set screw on the flat side of the shaft in hopes that it would just slide out. tried pulling on it but doesn't seem to want to budge. i don't want to force it and risk breaking something. when i finally get this thing out anyone have tips on cleaning it? or getting my hands on a replacement part?