Dual gear drive lubrication

Those cheap(15-20€ from banggood at the time of writing) dual gear drive extruders are pretty useful. They grip the filament very well and prevent sliping, they also almost necessary for flexible filaments. They are also more durable than the plastic ones included with most creality printers (like my ender 3), the stock plastic ones have the tendency to crack. While it is an easy and affordable upgrade it has one issue, it lacks proper lubrication.

I had mine for about two years before it started doing a clicking noise and soon a loud clunking noise, it has especially noticeable during retraction. I also started noticing a black dust forming near the gears. As you can see in the images bellow there was severe wear on the axle (The screw that held the bearing), the bearing itself and also the aluminum housing.

The design itself is not ideal, the screw and the bearing have some play also the screw surface is not flat and does not make full contact with the bearing. I would recommend not setting the extruder too tight because it will accelerate wear. You can also reduce wear by properly lubricating the bearing, most extruders from factory have almost no lubrication ! I got a new one and i used some lithium grease on the bearing with a toothpick and a bit on the top and bottom part of the gear, don’t use too much because you risk getting lube on the filament and it is not a good idea. Occasionally there are improved versions of this extruder with bushings above and bellow the gear and a smooth shaft, i would also suggest checking if they are properly lubed before using.