This is a Custom Flatbed modeled, added some stacks and stuff one. This needs to be put on your truck in Giants editor and it june need resizing depening on your truck size just change the X, Y, Z of the main transform group for the Flatbed and You Should Be set.
Parts: Drop Hitch, Reese Hitch, 5th Wheel – Catfish_John1979;
Stacks: Google Sketchup – steelgiant8;
Mudflaps: Google Sketchup – Jake G.;
Flatbed Model – Fsfarmer11.