i'm running into a strange issue. not sure if something got corrupted in the last update of the stl files.
i downloaded the most recent files because i switched computers and i needed to run out another set of axles.
the new axle that came out instantly started making popping sounds when i tested the new truck.
i tracked the problem to the upper counter gear between the bevel and the lower diff. there suddenly seems to be too much back lash between those gears and now the upper counter gear is skipping on the diff gear under load. i managed to force the gears to fail so i could see the issue clearly. i can see no movement between the top of the axle cover and the center section. i laid the parts in fusion 360 because i also want to beef up the mounting hardware that is cracking under stress from the walls being too thin for PLA. but if you could check the tolerances again on the axle case and counter gear and lower diff gear. the Bevel gears are fine.
I thought to splice the axle case and drop the countergear down .1-.2mm and see if it would be enough to tighten the backlash and stop the gears from skipping under load. I tried to tighten up the lower tolerance because i thought there was too much play in the lower diff bearing holders but that part is fine so i went back to the original tolerance.
i believe this is the issue Marcus24 is talking about in his post.
also i notice the top axle cover shape is odd for the bevel/input shaft it is elongated and not round and doesn't fit the curve profile of the center axle section, there is no play up and down with the countergear bearing and shaft but it looks like the cover is from a different version of the axle case, the curve of the bearing holder looks like the parts split was in the wrong spot(higher then it should be)