A wrench to tighten your truck simulator shift knob to your shifter with a 13mm jam nut, like the one included with "amazon shifters". You'll need to move the shifter into a forward gear and sneak this around the shift shaft between the collar and rotate it up in there. It works well in PLA+, though something stronger would be idea.
Eaton_Shift_Knob_Wrench.stl | 199.7KB |