So, in the pursuit of modding knowledge, I tried to extend the bullbars on the D Series, and it worked. I then edited the jbeam to give them proper collisions, and it worked. I then put it into the proper mod folder format, and the body of the truck disappeared. An image of that can be seen below. Any ideas on what went wrong? note: the jbeam of the body was still there.
In this case its a jbeam problem, not a model problem. Something must of got messed up in the model name, or the jbeam is broken. Ill tell you its not the 3d model