Now, I would assume you cannot make the logo texture transparent, correct?
You are correct, ET44C4. It's one weakness of the original model. I think it has to do with the material properties of the part. Anyway, I've just done it the hard way by trying to match the logo part background color the same as the cab color. Copy that portion of the cab onto the logo texture file as a background color. Even then, in certain lighting conditions, you can still see the box.
Best,
tagsdm