I have an Aero on my printer, and gotten probably 40 hours of print time from it with great results. Last night at about 5 layers into a print, the extruder started clicking and nothing but an inconsistent skinny string of filament was coming out. I've taken the Aero apart and put it together again a few times now, each time the extruder appears to work fine from a cold start for a minute or so, then the clicking inevitably starts. The click only seems to happen on extrudes, not retracts. Here's a brief video : Here are some things I've tried so far... - I checked for a clog, filament can be manually pushed through the hotend without a problem. - I increased voltage on the stepper driver, but no change in behavior - Checked that pinion and black gear are flush - Checked that filament guide is more or less hitting the center of the hobbed gear (it's not 100% center, but hasn't been a problem until now, see photo) - I replaced the extruders stepper motor (a pancake stepper, this one) with the stock stepper. No change. - I replaced the stock stepper driver (an A4988) with a DRV8825. Still clicks. I'm about at my wits end. Are there any other things I should try before binning this extruder?