Thanks, I'm quite happy how ii has evolved so far. The print quality is also quite good after all the work put into it.

Took apart the extruders and did some comparison between the gears. Seems there's 2 types of gears, the ones with shallower groove don't have a bewel on the top gears and generally seem better quality. The other type seem to have some smaal variances in the depth of the groove which isn't good of course. Also they seem to have already started to show some wear on the top gears, which suggests that the metal is subpar. Well not that suprising when getting them cheap. Also I ordered them in multiple patches, partly because the first order didn't have correct parts and had to reorder more gears.
IMG_20200724_191752.jpgIMG_20200724_192642.jpgIMG_20200724_192718.jpgIMG_20200724_193150.jpg

I matched the gears as best as possible. Also since I'll probably replace at least the worse gears, I used a Dremel to deepen the idler side gears top teeth, making the gears mesh bit closer. Didn't touch the better ones, though. Probably just made things worse and the gears will wear out even faster. But wanted to experiment a bit.

While I had the extruders apart, I noticed that the idler arms isn't a perfect fit for the gears and had to file away a bit to make the idler close fully. Either my modeling is a bit off, or ABS has shrunk enough to cause this. Now the idler arms close fully and the grip seems a lot better. So in the end the gears weren't the main problem.

Time to do a test print and hope the tool changes work this time. Just don't know what to print, don't want to start a long print. A 6 colored Benchy? Haven't done that before...