My extruder has a problem.
My extruder has a problem.

video_2023-08-25_09-49-56

I shared a video of the problem, it's hard to describe with words. Can you help me solve it?
My extruder has a problem.
video_2023-08-25_09-49-56
I shared a video of the problem, it's hard to describe with words. Can you help me solve it?
That doesn't sound like the gear slipping to me, it sounds like the stepper motor trying, and failing, to step. My i3 clone would do this when:
Assuming you're preheated, remove the filament from your extruder, cut about 5 cm off, and give it another go. Note that you may need to unclog your nozzle with a cold pull, but on my i3 it tended to clog at the extruder gear.
Another thing that can cause this is if the extruder motor overheats. Is the cold end fan running? Is the motor hot to the touch?
I was able to remove the filament, and I cut some off and reinserted it, but the same thing happened.
Is your nozzle clogged? I would remove your nozzle and see if you can extrude cold. If you can, there's a clog in your nozzle. If you can't then there's something upstream preventing filament from moving.
Take the nozzle out and see if you can feed the filament through then. That'll tell you whether it's a clogged nozzle (most likely) or stepper/bearing/driver issues (less likely).
I just checked youtube video about your extruder. I couldnt find how to change tension tho.
To inspect gear it should be possible to see it from above (around the spot where filament enters extruder). Maybe you can try to heat up to 210C and then disable stepper motors and push filament by hand (or using that wheel on front side of extruder). Or just remove filament and try extruding to see if motor is working normaly.
It could be that hotend is clogged or maybe your motor cable is lose (assuming it was working fine before). More likely a clog, and you should probably dissasemble extruder and clean, but you can also try cold pulls (google that, you heat up to lower temp and pull the filament with hand to remove if soemthing was stuck there).
What retraction distance you use? If retraction distance is too high and extruder fan not powerfull enough, hot filament can go too far in the cold part of extruder and then it can deform and cool down and gets stuck there. Motor can usually overcome that force and grind trough filament, but thats not your case, your motor cant rotate at all. Thats why I said maybe lose cable, but it could be that your motor curent is just set that low and I wouldnt touch it if it was working before. Another cause could be stepper driver overheating, but that usually happens while printing long print jobs, so not likely here I think.
It sounds like the gear is slipping are you using a single or dual gear extruder?
Dual is recommended imo. But some things you can look at are if the tension on the extruder gear is too high or low it can cause chatter or slippage. Also high friction on the spool can cause slippage so make sure the filament spool spins with little effort.
If none of this works look at the gear it's possible it's just warn out and not catching the filament.
How do I inspect the gear? Also, I only got this printer a few weeks ago, so it shouldn't be worn out already?
The extruder, motor, and/or gear itself is not the problem here. Your problem is likely in the hot end. I see people make this mistake all the time.
Take apart the print head and fix it. If you're not a fan of taking things apart and putting them back together, 3D printing will not be a fun hobby for you.