We like Barspin´s Toy Dump Truck (https://cults3d.com/en/game/toy-dump-truck) and we keep it busy transporting candy around the office. Although it does a decent job we felt we needed to add a trailer to get the most of it so we designed this trailer where the box is about half the size of the original truck.
Print all the parts needed.
Connect the trailer to the dumptruck and attach the lock pin and washer to secure the trailer to the dumo truck.
As with the original dump truck the wheels are pushed onto the wheel axle using a little force. The wheel axle itself can be mounted to the base using either 2 countersunk M3 screws or simply push two pieces of 3mm filament in their place.