Well here's the Dump Truck I've been working on. It has a working V6 engine, HOG steering, and the dump can go up and down by turning the yellow Knob Gear. You can move the seats forward and back, recline them, and open the doors.
I changed the truck around a little. I added mirrors and headlights and made the dump go up and down pneumatically. The pneumatic cylinder is pumped by a small blue pneumatic pump.
Pictures