I have a customer requesting a Tonka Truck & I am curious at how to make the 3D Tonka Truck. I hope that someone can help me! I am new here so hello to everyone!! I attached a picture of what I am talking about.

Welcome!
The third one down on the link shows step by step in buttercream. The picture you have is covered in fondant with fondant covered doughnuts for wheels.
http://www.coolest-kid-birthday-parties.com/cake-ideas.html
Feel free to ask questions. That's why we are here!