Truck With Swappable Bed Attachments

This thing was made with Tinkercad. Edit it online

Truck Body/Bed
https://tinkercad.com/things/fCN4YMhTmQQ

Cement Mixer:
https://tinkercad.com/things/4Ra3JgwyawS

Dump Truck:
https://tinkercad.com/things/43HThTLBXk4-truckdumper

I created this truck body with lips on the bed's sides into which some other part can be slid. Currently, there are two swappable parts: a cement mixer, and a dump truck.

This was my first attempt to create something from scratch that had "encapsulated wheel-axels" and I realize now that the parts, which are relatively small, sometimes melt together, as with the PLA I used.

I tried to fix this with one of those detachable-jawed pliers and a razor-knife. I had partial success, but this is nothing any competent micro-surgeon shouldn't be able to fix. Maybe I'll make the thing a bit larger next time.

The cement mixer spins, if you work it. The dumper is supposed to tilt, but I wasn't as patient with it.