I used the GB03 on the rear axle and I get no friction between the top gear and the diff gear. In front it works, because the direction is changed and the upper gear will be pressed down. On the rear axle the upper gear will be lift up a bit and get no friction.
The car is not running. I reprinted all components and assambled complete new parts, but the truck won't drive.
Have anyone the same problem? What can I do?